Related
I have the following JQuery code:
$(document).ready(function () {
var $containerHeight = $(window).height();
if ($containerHeight <= 818) {
$('.footer').css({
position: 'static',
bottom: 'auto',
left: 'auto'
});
}
if ($containerHeight > 819) {
$('.footer').css({
position: 'absolute',
bottom: '3px',
left: '0px'
});
}
});
The only problem is that this only works when the browser first loads, I want containerHeight to also be checked when they are resizing the window?
Any ideas?
Here's an example using jQuery, javascript and css to handle resize events.
(css if your best bet if you're just stylizing things on resize (media queries))
http://jsfiddle.net/CoryDanielson/LAF4G/
css
.footer
{
/* default styles applied first */
}
#media screen and (min-height: 820px) /* height >= 820 px */
{
.footer {
position: absolute;
bottom: 3px;
left: 0px;
/* more styles */
}
}
javascript
window.onresize = function() {
if (window.innerHeight >= 820) { /* ... */ }
if (window.innerWidth <= 1280) { /* ... */ }
}
jQuery
$(window).on('resize', function(){
var win = $(this); //this = window
if (win.height() >= 820) { /* ... */ }
if (win.width() >= 1280) { /* ... */ }
});
How do I stop my resize code from executing so often!?
This is the first problem you'll notice when binding to resize. The resize code gets called a LOT when the user is resizing the browser manually, and can feel pretty janky.
To limit how often your resize code is called, you can use the debounce or throttle methods from the underscore & lodash libraries.
debounce will only execute your resize code X number of milliseconds after the LAST resize event. This is ideal when you only want to call your resize code once, after the user is done resizing the browser. It's good for updating graphs, charts and layouts that may be expensive to update every single resize event.
throttle will only execute your resize code every X number of milliseconds. It "throttles" how often the code is called. This isn't used as often with resize events, but it's worth being aware of.
If you don't have underscore or lodash, you can implement a similar solution yourself:
JavaScript/JQuery: $(window).resize how to fire AFTER the resize is completed?
Move your javascript into a function and then bind that function to window resize.
$(document).ready(function () {
updateContainer();
$(window).resize(function() {
updateContainer();
});
});
function updateContainer() {
var $containerHeight = $(window).height();
if ($containerHeight <= 818) {
$('.footer').css({
position: 'static',
bottom: 'auto',
left: 'auto'
});
}
if ($containerHeight > 819) {
$('.footer').css({
position: 'absolute',
bottom: '3px',
left: '0px'
});
}
}
Try this solution. Only fires once the page loads and then during window resize at predefined resizeDelay.
$(document).ready(function()
{
var resizeDelay = 200;
var doResize = true;
var resizer = function () {
if (doResize) {
//your code that needs to be executed goes here
doResize = false;
}
};
var resizerInterval = setInterval(resizer, resizeDelay);
resizer();
$(window).resize(function() {
doResize = true;
});
});
jQuery has a resize event handler which you can attach to the window, .resize(). So, if you put $(window).resize(function(){/* YOUR CODE HERE */}) then your code will be run every time the window is resized.
So, what you want is to run the code after the first page load and whenever the window is resized. Therefore you should pull the code into its own function and run that function in both instances.
// This function positions the footer based on window size
function positionFooter(){
var $containerHeight = $(window).height();
if ($containerHeight <= 818) {
$('.footer').css({
position: 'static',
bottom: 'auto',
left: 'auto'
});
}
else {
$('.footer').css({
position: 'absolute',
bottom: '3px',
left: '0px'
});
}
}
$(document).ready(function () {
positionFooter();//run when page first loads
});
$(window).resize(function () {
positionFooter();//run on every window resize
});
See: Cross-browser window resize event - JavaScript / jQuery
Give your anonymous function a name, then:
$(window).on("resize", doResize);
http://api.jquery.com/category/events/
function myResizeFunction() {
...
}
$(function() {
$(window).resize(myResizeFunction).trigger('resize');
});
This will cause your resize handler to trigger on window resize and on document ready. Of course, you can attach your resize handler outside of the document ready handler if you want .trigger('resize') to run on page load instead.
UPDATE: Here's another option if you don't want to make use of any other third-party libraries.
This technique adds a specific class to your target element so you have the advantage of controlling the styling through CSS only (and avoiding inline styling).
It also ensures that the class is only added or removed when the actual threshold point is triggered and not on each and every resize. It will fire at one threshold point only: when the height changes from <= 818 to > 819 or vice versa and not multiple times within each region. It's not concerned with any change in width.
function myResizeFunction() {
var $window = $(this),
height = Math.ceil($window.height()),
previousHeight = $window.data('previousHeight');
if (height !== previousHeight) {
if (height < 819)
previousHeight >= 819 && $('.footer').removeClass('hgte819');
else if (!previousHeight || previousHeight < 819)
$('.footer').addClass('hgte819');
$window.data('previousHeight', height);
}
}
$(function() {
$(window).on('resize.optionalNamespace', myResizeFunction).triggerHandler('resize.optionalNamespace');
});
As an example, you might have the following as some of your CSS rules:
.footer {
bottom: auto;
left: auto;
position: static;
}
.footer.hgte819 {
bottom: 3px;
left: 0;
position: absolute;
}
Use this:
window.onresize = function(event) {
...
}
can use it too
function getWindowSize()
{
var fontSize = parseInt($("body").css("fontSize"), 10);
var h = ($(window).height() / fontSize).toFixed(4);
var w = ($(window).width() / fontSize).toFixed(4);
var size = {
"height": h
,"width": w
};
return size;
}
function startResizeObserver()
{
//---------------------
var colFunc = {
"f10" : function(){ alert(10); }
,"f50" : function(){ alert(50); }
,"f100" : function(){ alert(100); }
,"f500" : function(){ alert(500); }
,"f1000" : function(){ alert(1000);}
};
//---------------------
$(window).resize(function() {
var sz = getWindowSize();
if(sz.width > 10){colFunc['f10']();}
if(sz.width > 50){colFunc['f50']();}
if(sz.width > 100){colFunc['f100']();}
if(sz.width > 500){colFunc['f500']();}
if(sz.width > 1000){colFunc['f1000']();}
});
}
$(document).ready(function()
{
startResizeObserver();
});
You can bind resize using .resize() and run your code when the browser is resized. You need to also add an else condition to your if statement so that your css values toggle the old and the new, rather than just setting the new.
There was another thread about this, which I've tried. But there is one problem: the textarea doesn't shrink if you delete the content. I can't find any way to shrink it to the correct size - the clientHeight value comes back as the full size of the textarea, not its contents.
The code from that page is below:
function FitToContent(id, maxHeight)
{
var text = id && id.style ? id : document.getElementById(id);
if ( !text )
return;
var adjustedHeight = text.clientHeight;
if ( !maxHeight || maxHeight > adjustedHeight )
{
adjustedHeight = Math.max(text.scrollHeight, adjustedHeight);
if ( maxHeight )
adjustedHeight = Math.min(maxHeight, adjustedHeight);
if ( adjustedHeight > text.clientHeight )
text.style.height = adjustedHeight + "px";
}
}
window.onload = function() {
document.getElementById("ta").onkeyup = function() {
FitToContent( this, 500 )
};
}
A COMPLETE YET SIMPLE SOLUTION
Updated 2022-08-30
(Added support for single row multiple textbox by default)
The following code will work:
On key input.
With pasted text (right click & ctrl+v).
With cut text (right click & ctrl+x).
With pre-loaded text.
With all textarea's (multiline textbox's) site wide.
With Firefox (v31-109 tested).
With Chrome (v37-108 tested).
With IE (v9-v11 tested).
With Edge (v14-v108 tested).
With IOS Safari.
With Android Browser.
With JavaScript strict mode.
OPTION 1 (With jQuery)
This option requires jQuery and has been tested and is working with 1.7.2 - 3.6.3
Simple (Add this jQuery code to your master script file and forget about it.)
$("textarea").each(function () {
this.setAttribute("style", "height:" + (this.scrollHeight) + "px;overflow-y:hidden;");
}).on("input", function () {
this.style.height = 0;
this.style.height = (this.scrollHeight) + "px";
});
<script src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.6.3.min.js"></script>
<textarea placeholder="Type, paste, cut text here...">PRELOADED TEXT.
This JavaScript should now add better support for IOS browsers and Android browsers.</textarea>
<textarea placeholder="Type, paste, cut text here..."></textarea>
Test on jsfiddle
OPTION 2 (Pure JavaScript)
Simple (Add this JavaScript to your master script file and forget about it.)
const tx = document.getElementsByTagName("textarea");
for (let i = 0; i < tx.length; i++) {
tx[i].setAttribute("style", "height:" + (tx[i].scrollHeight) + "px;overflow-y:hidden;");
tx[i].addEventListener("input", OnInput, false);
}
function OnInput() {
this.style.height = 0;
this.style.height = (this.scrollHeight) + "px";
}
<textarea placeholder="Type, paste, cut text here...">PRELOADED TEXT. This JavaScript should now add better support for IOS browsers and Android browsers.</textarea>
<textarea placeholder="Type, paste, cut text here..."></textarea>
Test on jsfiddle
OPTION 3 (jQuery Extension)
Useful if you want to apply further chaining to the textareas, you want to be auto-sized.
jQuery.fn.extend({
autoHeight: function () {
function autoHeight_(element) {
return jQuery(element)
.css({ "height": 0, "overflow-y": "hidden" })
.height(element.scrollHeight);
}
return this.each(function() {
autoHeight_(this).on("input", function() {
autoHeight_(this);
});
});
}
});
Invoke with $("textarea").autoHeight()
UPDATING TEXTAREA VIA JAVASCRIPT
When injecting content into a textarea via JavaScript, append the following code to invoke the function in option 1.
$("textarea").trigger("input");
PRESET TEXTAREA HEIGHT
To fix the initial height of the textarea you will need to add another condition:
const txHeight = 16;
const tx = document.getElementsByTagName("textarea");
for (let i = 0; i < tx.length; i++) {
if (tx[i].value == '') {
tx[i].setAttribute("style", "height:" + txHeight + "px;overflow-y:hidden;");
} else {
tx[i].setAttribute("style", "height:" + (tx[i].scrollHeight) + "px;overflow-y:hidden;");
}
tx[i].addEventListener("input", OnInput, false);
}
function OnInput(e) {
this.style.height = 0;
this.style.height = (this.scrollHeight) + "px";
}
<textarea placeholder="Type, paste, cut text here...">PRELOADED TEXT. This JavaScript should now add better support for IOS browsers and Android browsers.</textarea>
<textarea placeholder="Type, paste, cut text here..."></textarea>
This works for me (Firefox 3.6/4.0 and Chrome 10/11):
var observe;
if (window.attachEvent) {
observe = function (element, event, handler) {
element.attachEvent('on'+event, handler);
};
}
else {
observe = function (element, event, handler) {
element.addEventListener(event, handler, false);
};
}
function init () {
var text = document.getElementById('text');
function resize () {
text.style.height = 'auto';
text.style.height = text.scrollHeight+'px';
}
/* 0-timeout to get the already changed text */
function delayedResize () {
window.setTimeout(resize, 0);
}
observe(text, 'change', resize);
observe(text, 'cut', delayedResize);
observe(text, 'paste', delayedResize);
observe(text, 'drop', delayedResize);
observe(text, 'keydown', delayedResize);
text.focus();
text.select();
resize();
}
textarea {
border: 0 none white;
overflow: hidden;
padding: 0;
outline: none;
background-color: #D0D0D0;
}
<body onload="init();">
<textarea rows="1" style="height:1em;" id="text"></textarea>
</body>
If you want try it on jsfiddle
It starts with a single line and grows only the exact amount necessary. It is ok for a single textarea, but I wanted to write something where I would have many many many such textareas (about as much as one would normally have lines in a large text document). In that case it is really slow. (In Firefox it's insanely slow.) So I really would like an approach that uses pure CSS. This would be possible with contenteditable, but I want it to be plaintext-only.
jQuery solution
adjust the css to match your requirements
css...
div#container textarea {
min-width: 270px;
width: 270px;
height: 22px;
line-height: 24px;
min-height: 22px;
overflow-y: hidden; /* fixes scrollbar flash - kudos to #brettjonesdev */
padding-top: 1.1em; /* fixes text jump on Enter keypress */
}
javascript...
// auto adjust the height of
$('#container').delegate( 'textarea', 'keydown', function (){
$(this).height( 0 );
$(this).height( this.scrollHeight );
});
$('#container').find( 'textarea' ).keydown();
OR alternative for jQuery 1.7+...
// auto adjust the height of
$('#container').on( 'keyup', 'textarea', function (){
$(this).height( 0 );
$(this).height( this.scrollHeight );
});
$('#container').find( 'textarea' ).keyup();
I've created a fiddle with the absolute minimum styling as a starting point for your experiments...
http://jsfiddle.net/53eAy/951/
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Textarea autoresize</title>
<style>
textarea {
overflow: hidden;
}
</style>
<script>
function resizeTextarea(ev) {
this.style.height = '24px';
this.style.height = this.scrollHeight + 12 + 'px';
}
var te = document.querySelector('textarea');
te.addEventListener('input', resizeTextarea);
</script>
</head>
<body>
<textarea></textarea>
</body>
</html>
Tested in Firefox 14 and Chromium 18. The numbers 24 and 12 are arbitrary, test to see what suits you best.
You could do without the style and script tags, but it becomes a bit messy imho (this is old style HTML+JS and is not encouraged).
<textarea style="overflow: hidden" onkeyup="this.style.height='24px'; this.style.height = this.scrollHeight + 12 + 'px';"></textarea>
Edit: modernized code. Changed onkeyup attribute to addEventListener.
Edit: keydown works better than keyup
Edit: declare function before using
Edit: input works better than keydown (thnx #WASD42 & #MA-Maddin)
jsfiddle
The best solution (works and is short) for me is:
$(document).on('input', 'textarea', function () {
$(this).outerHeight(38).outerHeight(this.scrollHeight); // 38 or '1em' -min-height
});
It works like a charm without any blinking with paste (with mouse also), cut, entering and it shrinks to the right size.
Please take a look at jsFiddle.
Found an one liner from here;
<textarea name="text" oninput="this.style.height = ''; this.style.height = this.scrollHeight +'px'"></textarea>
If you don’t need to support IE8 you can use the input event:
var resizingTextareas = [].slice.call(document.querySelectorAll('textarea[autoresize]'));
resizingTextareas.forEach(function(textarea) {
textarea.addEventListener('input', autoresize, false);
});
function autoresize() {
this.style.height = 'auto';
this.style.height = this.scrollHeight+'px';
this.scrollTop = this.scrollHeight;
window.scrollTo(window.scrollLeft,(this.scrollTop+this.scrollHeight));
}
Now you only need to add some CSS and you are done:
textarea[autoresize] {
display: block;
overflow: hidden;
resize: none;
}
Usage:
<textarea autoresize>Type here and I’ll resize.</textarea>
You can read more about how it works on my blog post.
You're using the higher value of the current clientHeight and the content scrollHeight. When you make the scrollHeight smaller by removing content, the calculated area can't get smaller because the clientHeight, previously set by style.height, is holding it open. You could instead take a max() of scrollHeight and a minimum height value you have predefined or calculated from textarea.rows.
In general you probably shouldn't really rely on scrollHeight on form controls. Apart from scrollHeight being traditionally less widely-supported than some of the other IE extensions, HTML/CSS says nothing about how form controls are implemented internally and you aren't guaranteed scrollHeight will be anything meaningful. (Traditionally some browsers have used OS widgets for the task, making CSS and DOM interaction on their internals impossible.) At least sniff for scrollHeight/clientHeight's existance before trying to enable the effect.
Another possible alternative approach to avoid the issue if it's important that it work more widely might be to use a hidden div sized to the same width as the textarea, and set in the same font. On keyup, you copy the text from the textarea to a text node in hidden div (remembering to replace '\n' with a line break, and escape '<'/'&' properly if you're using innerHTML). Then simply measuring the div's offsetHeight will give you the height you need.
autosize
https://github.com/jackmoore/autosize
Just works, standalone, is popular (3.0k+ GitHub stars as of October 2018), available on cdnjs) and lightweight (~3.5k). Demo:
<textarea id="autosize" style="width:200px;">a
J b
c</textarea>
<script src="https://cdnjs.cloudflare.com/ajax/libs/autosize.js/4.0.2/autosize.min.js"></script>
<script>autosize(document.querySelectorAll('#autosize'));</script>
BTW, if you are using the ACE editor, use maxLines: Infinity: Automatically adjust height to contents in Ace Cloud 9 editor
As a different approach, you can use a <span> which adjusts its size automatically. You will need make it editable by adding the contenteditable="true" property and you're done:
div {
width: 200px;
}
span {
border: 1px solid #000;
padding: 5px;
}
<div>
<span contenteditable="true">This text can be edited by the user</span>
</div>
The only issue with this approach is that if you want to submit the value as part of the form, you'll have to do so by yourself in JavaScript. Doing so is relatively easy. For example, you can add a hidden field and in the onsubmit event of the form assign the value of the span to the hidden field which will be then automatically submitted with the form.
There is a slightly different approach.
<div style="position: relative">
<pre style="white-space: pre-wrap; word-wrap: break-word"></pre>
<textarea style="position: absolute; top: 0; left: 0; width: 100%; height: 100%"></textarea>
</div>
The idea is to copy the text from textarea into the pre and let CSS make sure that they have the same size.
The benefit is that frameworks present simple tools to move text around without touching any events. Namely, in AngularJS you would add a ng-model="foo" ng-trim="false" to the textarea and ng-bind="foo + '\n'" to the pre. See a fiddle.
Just make sure that pre has the same font size as the textarea.
Has anyone considered contenteditable? No messing around with scrolling,a nd the only JS I like about it is if you plan on saving the data on blur... and apparently, it's compatible on all of the popular browsers : http://caniuse.com/#feat=contenteditable
Just style it to look like a text box, and it autosizes... Make its min-height the preferred text height and have at it.
What's cool about this approach is that you can save and tags on some of the browsers.
http://jsfiddle.net/gbutiri/v31o8xfo/
var _auto_value = '';
$(document).on('blur', '.autosave', function(e) {
var $this = $(this);
if ($this.text().trim() == '') {
$this.html('');
}
// The text is here. Do whatever you want with it.
$this.addClass('saving');
if (_auto_value !== $this.html() || $this.hasClass('error')) {
// below code is for example only.
$.ajax({
url: '/echo/json/?action=xyz_abc',
data: 'data=' + $this.html(),
type: 'post',
datatype: 'json',
success: function(d) {
console.log(d);
$this.removeClass('saving error').addClass('saved');
var k = setTimeout(function() {
$this.removeClass('saved error')
}, 500);
},
error: function() {
$this.removeClass('saving').addClass('error');
}
});
} else {
$this.removeClass('saving');
}
}).on('focus mouseup', '.autosave', function() {
var $this = $(this);
if ($this.text().trim() == '') {
$this.html('');
}
_auto_value = $this.html();
}).on('keyup', '.autosave', function(e) {
var $this = $(this);
if ($this.text().trim() == '') {
$this.html('');
}
});
body {
background: #3A3E3F;
font-family: Arial;
}
label {
font-size: 11px;
color: #ddd;
}
.autoheight {
min-height: 16px;
font-size: 16px;
margin: 0;
padding: 10px;
font-family: Arial;
line-height: 20px;
box-sizing: border-box;
-o-box-sizing: border-box;
-moz-box-sizing: border-box;
-webkit-box-sizing: border-box;
overflow: hidden;
display: block;
resize: none;
border: 0;
outline: none;
min-width: 200px;
background: #ddd;
max-height: 400px;
overflow: auto;
}
.autoheight:hover {
background: #eee;
}
.autoheight:focus {
background: #fff;
}
.autosave {
-webkit-transition: all .2s;
-moz-transition: all .2s;
transition: all .2s;
position: relative;
float: none;
}
.autoheight * {
margin: 0;
padding: 0;
}
.autosave.saving {
background: #ff9;
}
.autosave.saved {
background: #9f9;
}
.autosave.error {
background: #f99;
}
.autosave:hover {
background: #eee;
}
.autosave:focus {
background: #fff;
}
[contenteditable=true]:empty:before {
content: attr(placeholder);
color: #999;
position: relative;
top: 0px;
/*
For IE only, do this:
position: absolute;
top: 10px;
*/
cursor: text;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<label>Your Name</label>
<div class="autoheight autosave contenteditable" contenteditable="true" placeholder="Your Name"></div>
The following works for cutting, pasting, etc., regardless of whether those actions are from the mouse, a keyboard shortcut, selecting an option from a menu bar ... several answers take a similar approach but they don't account for box-sizing, which is why they incorrectly apply the style overflow: hidden.
I do the following, which also works well with max-height and rows for minimum and maximum height.
function adjust() {
var style = this.currentStyle || window.getComputedStyle(this);
var boxSizing = style.boxSizing === 'border-box'
? parseInt(style.borderBottomWidth, 10) +
parseInt(style.borderTopWidth, 10)
: 0;
this.style.height = '';
this.style.height = (this.scrollHeight + boxSizing) + 'px';
};
var textarea = document.getElementById("ta");
if ('onpropertychange' in textarea) { // IE
textarea.onpropertychange = adjust;
} else if ('oninput' in textarea) {
textarea.oninput = adjust;
}
setTimeout(adjust.bind(textarea));
textarea {
resize: none;
max-height: 150px;
border: 1px solid #999;
outline: none;
font: 18px sans-serif;
color: #333;
width: 100%;
padding: 8px 14px;
box-sizing: border-box;
}
<textarea rows="3" id="ta">
Try adding several lines to this.
</textarea>
For absolute completeness, you should call the adjust function in a few more circumstances:
Window resize events, if the width of the textarea changes with window resizing, or other events that change the width of the textarea
When the textarea's display style attribute changes, e.g. when it goes from none (hidden) to block
When the value of the textarea is changed programmatically
Note that using window.getComputedStyle or getting currentStyle can be somewhat computationally expensive, so you may want to cache the result instead.
Works for IE6, so I really hope that's good enough support.
I used the following code for multiple textareas. Working fine in Chrome 12, Firefox 5 and IE 9, even with delete, cut and paste actions performed in the textareas.
function attachAutoResizeEvents() {
for (i = 1; i <= 4; i++) {
var txtX = document.getElementById('txt' + i)
var minH = txtX.style.height.substr(0, txtX.style.height.indexOf('px'))
txtX.onchange = new Function("resize(this," + minH + ")")
txtX.onkeyup = new Function("resize(this," + minH + ")")
txtX.onchange(txtX, minH)
}
}
function resize(txtX, minH) {
txtX.style.height = 'auto' // required when delete, cut or paste is performed
txtX.style.height = txtX.scrollHeight + 'px'
if (txtX.scrollHeight <= minH)
txtX.style.height = minH + 'px'
}
window.onload = attachAutoResizeEvents
textarea {
border: 0 none;
overflow: hidden;
outline: none;
background-color: #eee
}
<textarea style='height:100px;font-family:arial' id="txt1"></textarea>
<textarea style='height:125px;font-family:arial' id="txt2"></textarea>
<textarea style='height:150px;font-family:arial' id="txt3"></textarea>
<textarea style='height:175px;font-family:arial' id="txt4"></textarea>
A bit corrections. Works perfectly in Opera
$('textarea').bind('keyup keypress', function() {
$(this).height('');
var brCount = this.value.split('\n').length;
this.rows = brCount+1; //++ To remove twitching
var areaH = this.scrollHeight,
lineHeight = $(this).css('line-height').replace('px',''),
calcRows = Math.floor(areaH/lineHeight);
this.rows = calcRows;
});
I Don't know if anyone mention this way but in some cases it's possible to resize the height with rows Attribute
textarea.setAttribute('rows',breaks);
Demo
Here is an angularjs directive for panzi's answer.
module.directive('autoHeight', function() {
return {
restrict: 'A',
link: function(scope, element, attrs) {
element = element[0];
var resize = function(){
element.style.height = 'auto';
element.style.height = (element.scrollHeight)+'px';
};
element.addEventListener('change', resize, false);
element.addEventListener('cut', resize, false);
element.addEventListener('paste', resize, false);
element.addEventListener('drop', resize, false);
element.addEventListener('keydown',resize, false);
setTimeout(resize, 100);
}
};
});
HTML:
<textarea ng-model="foo" auto-height></textarea>
I know a short and correct way of implementing this with jquery.No extra hidden div needed and works in most browser
<script type="text/javascript">$(function(){
$("textarea").live("keyup keydown",function(){
var h=$(this);
h.height(60).height(h[0].scrollHeight);//where 60 is minimum height of textarea
});});
</script>
Some of the answers here don't account for padding.
Assuming you have a maxHeight you don't want to go over, this worked for me:
// obviously requires jQuery
// element is the textarea DOM node
var $el = $(element);
// inner height is height + padding
// outerHeight includes border (and possibly margins too?)
var padding = $el.innerHeight() - $el.height();
var originalHeight = $el.height();
// XXX: Don't leave this hardcoded
var maxHeight = 300;
var adjust = function() {
// reset it to the original height so that scrollHeight makes sense
$el.height(originalHeight);
// this is the desired height (adjusted to content size)
var height = element.scrollHeight - padding;
// If you don't want a maxHeight, you can ignore this
height = Math.min(height, maxHeight);
// Set the height to the new adjusted height
$el.height(height);
}
// The input event only works on modern browsers
element.addEventListener('input', adjust);
An even simpler, cleaner approach is this:
// adjust height of textarea.auto-height
$(document).on( 'keyup', 'textarea.auto-height', function (e){
$(this).css('height', 'auto' ); // you can have this here or declared in CSS instead
$(this).height( this.scrollHeight );
}).keyup();
// and the CSS
textarea.auto-height {
resize: vertical;
max-height: 600px; /* set as you need it */
height: auto; /* can be set here of in JS */
overflow-y: auto;
word-wrap:break-word
}
All that is needed is to add the .auto-height class to any textarea you want to target.
Tested in FF, Chrome and Safari. Let me know if this doesn't work for you, for any reason. But, this is the cleanest and simplest way I've found this to work. And it works great! :D
You can use JQuery to expand the textarea while typing:
$(document).find('textarea').each(function () {
var offset = this.offsetHeight - this.clientHeight;
$(this).on('keyup input focus', function () {
$(this).css('height', 'auto').css('height', this.scrollHeight + offset);
});
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div>
<textarea name="note"></textarea>
<div>
Those who want to achieve the same in new versions of Angular.
Grab textArea elementRef.
#ViewChild('textArea', { read: ElementRef }) textArea: ElementRef;
public autoShrinkGrow() {
textArea.style.overflow = 'hidden';
textArea.style.height = '0px';
textArea.style.height = textArea.scrollHeight + 'px';
}
<textarea (keyup)="autoGrow()" #textArea></textarea>
I am also adding another use case that may come handy some users reading the thread, when user want to increase the height of text-area to certain height and then have overflow:scroll on it, above method can be extended to achieve the mentioned use-case.
public autoGrowShrinkToCertainHeight() {
const textArea = this.textArea.nativeElement;
if (textArea.scrollHeight > 77) {
textArea.style.overflow = 'auto';
return;
}
else {
textArea.style.overflow = 'hidden';
textArea.style.height = '0px';
textArea.style.height = textArea.scrollHeight + 'px';
}
}
my implementation is very simple, count the number of lines in the input (and minimum 2 rows to show that it's a textarea):
textarea.rows = Math.max(2, textarea.value.split("\n").length) // # oninput
full working example with stimulus: https://jsbin.com/kajosolini/1/edit?html,js,output
(and this works with the browser's manual resize handle for instance)
This code works for pasting and select delete also.
onKeyPressTextMessage = function(){
var textArea = event.currentTarget;
textArea.style.height = 'auto';
textArea.style.height = textArea.scrollHeight + 'px';
};
<textarea onkeyup="onKeyPressTextMessage(event)" name="welcomeContentTmpl" id="welcomeContent" onblur="onblurWelcomeTitle(event)" rows="2" cols="40" maxlength="320"></textarea>
Here is the JSFiddle
I recommend the javascript library from http://javierjulio.github.io/textarea-autosize.
Per comments, add example codeblock on plugin usage:
<textarea class="js-auto-size" rows="1"></textarea>
<script src="http://code.jquery.com/jquery-2.1.0.min.js"></script>
<script src="jquery.textarea_autosize.min.js"></script>
<script>
$('textarea.js-auto-size').textareaAutoSize();
</script>
Minimum required CSS:
textarea {
box-sizing: border-box;
max-height: 160px; // optional but recommended
min-height: 38px;
overflow-x: hidden; // for Firefox (issue #5)
}
MakeTextAreaResisable that uses qQuery
function MakeTextAreaResisable(id) {
var o = $(id);
o.css("overflow-y", "hidden");
function ResizeTextArea() {
o.height('auto');
o.height(o[0].scrollHeight);
}
o.on('change', function (e) {
ResizeTextArea();
});
o.on('cut paste drop keydown', function (e) {
window.setTimeout(ResizeTextArea, 0);
});
o.focus();
o.select();
ResizeTextArea();
}
None of the answers seem to work. But this one works for me:
https://coderwall.com/p/imkqoq/resize-textarea-to-fit-content
$('#content').on( 'change keyup keydown paste cut', 'textarea', function (){
$(this).height(0).height(this.scrollHeight);
}).find( 'textarea' ).change();
Accepted answer is working fine. But that is lot of code for this simple functionality. The below code will do the trick.
$(document).on("keypress", "textarea", function (e) {
var height = $(this).css("height");
var iScrollHeight = $(this).prop("scrollHeight");
$(this).css('height',iScrollHeight);
});
An example implementation with React:
const {
useLayoutEffect,
useState,
useRef
} = React;
const TextArea = () => {
const ref = useRef();
const [value, setValue] = useState('Some initial text that both wraps and uses\nnew\nlines');
// This only tracks the auto-sized height so we can tell if the user has manually resized
const autoHeight = useRef();
useLayoutEffect(() => {
if (!ref.current) {
return;
}
if (
autoHeight.current !== undefined &&
ref.current.style.height !== autoHeight.current
) {
// don't auto size if the user has manually changed the height
return;
}
ref.current.style.height = "auto";
ref.current.style.overflow = "hidden";
const next = `${ref.current.scrollHeight}px`;
ref.current.style.height = next;
autoHeight.current = next;
ref.current.style.overflow = "auto";
}, [value, ref, autoHeight]);
return (
<textarea
ref={ref}
style={{
resize: 'vertical',
minHeight: '1em',
}}
value={value}
onChange={event => setValue(event.target.value)}
/>
);
}
ReactDOM.render(<TextArea />, document.getElementById('app'))
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/17.0.1/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/17.0.1/umd/react-dom.production.min.js"></script>
<div id="app"></div>
A simple way to do using React.
...
const textareaRef = useRef();
const handleChange = (e) => {
textareaRef.current.style.height = "auto";
textareaRef.current.style.height = textareaRef.current.scrollHeight + "px";
};
return <textarea ref={textareaRef} onChange={handleChange} />;
I am creating a chat using Ajax requests and I'm trying to get messages div to scroll to the bottom without much luck.
I am wrapping everything in this div:
#scroll {
height:400px;
overflow:scroll;
}
Is there a way to keep it scrolled to the bottom by default using JS?
Is there a way to keep it scrolled to the bottom after an ajax request?
Here's what I use on my site:
var objDiv = document.getElementById("your_div");
objDiv.scrollTop = objDiv.scrollHeight;
This is much easier if you're using jQuery scrollTop:
$("#mydiv").scrollTop($("#mydiv")[0].scrollHeight);
Try the code below:
const scrollToBottom = (id) => {
const element = document.getElementById(id);
element.scrollTop = element.scrollHeight;
}
You can also use Jquery to make the scroll smooth:
const scrollSmoothlyToBottom = (id) => {
const element = $(`#${id}`);
element.animate({
scrollTop: element.prop("scrollHeight")
}, 500);
}
Here is the demo
Here's how it works:
Ref: scrollTop, scrollHeight, clientHeight
using jQuery animate:
$('#DebugContainer').stop().animate({
scrollTop: $('#DebugContainer')[0].scrollHeight
}, 800);
Newer method that works on all current browsers:
this.scrollIntoView(false);
var mydiv = $("#scroll");
mydiv.scrollTop(mydiv.prop("scrollHeight"));
Works from jQuery 1.6
https://api.jquery.com/scrollTop/
http://api.jquery.com/prop/
alternative solution
function scrollToBottom(element) {
element.scroll({ top: element.scrollHeight, behavior: 'smooth' });
}
smooth scroll with Javascript:
document.getElementById('messages').scrollIntoView({ behavior: 'smooth', block: 'end' });
If you don't want to rely on scrollHeight, the following code helps:
$('#scroll').scrollTop(1000000);
Java Script:
document.getElementById('messages').scrollIntoView(false);
Scrolls to the last line of the content present.
My Scenario: I had an list of string, in which I had to append a string given by a user and scroll to the end of the list automatically. I had fixed height of the display of the list, after which it should overflow.
I tried #Jeremy Ruten's answer, it worked, but it was scrolling to the (n-1)th element. If anybody is facing this type of issue, you can use setTimeOut() method workaround. You need to modify the code to below:
setTimeout(() => {
var objDiv = document.getElementById('div_id');
objDiv.scrollTop = objDiv.scrollHeight
}, 0)
Here is the StcakBlitz link I have created which shows the problem and its solution : https://stackblitz.com/edit/angular-ivy-x9esw8
If your project targets modern browsers, you can now use CSS Scroll Snap to control the scrolling behavior, such as keeping any dynamically generated element at the bottom.
.wrapper > div {
background-color: white;
border-radius: 5px;
padding: 5px 10px;
text-align: center;
font-family: system-ui, sans-serif;
}
.wrapper {
display: flex;
padding: 5px;
background-color: #ccc;
border-radius: 5px;
flex-direction: column;
gap: 5px;
margin: 10px;
max-height: 150px;
/* Control snap from here */
overflow-y: auto;
overscroll-behavior-y: contain;
scroll-snap-type: y mandatory;
}
.wrapper > div:last-child {
scroll-snap-align: start;
}
<div class="wrapper">
<div>01</div>
<div>02</div>
<div>03</div>
<div>04</div>
<div>05</div>
<div>06</div>
<div>07</div>
<div>08</div>
<div>09</div>
<div>10</div>
</div>
You can use the HTML DOM scrollIntoView Method like this:
var element = document.getElementById("scroll");
element.scrollIntoView();
Javascript or jquery:
var scroll = document.getElementById('messages');
scroll.scrollTop = scroll.scrollHeight;
scroll.animate({scrollTop: scroll.scrollHeight});
Css:
.messages
{
height: 100%;
overflow: auto;
}
Using jQuery, scrollTop is used to set the vertical position of scollbar for any given element. there is also a nice jquery scrollTo plugin used to scroll with animation and different options (demos)
var myDiv = $("#div_id").get(0);
myDiv.scrollTop = myDiv.scrollHeight;
if you want to use jQuery's animate method to add animation while scrolling down, check the following snippet:
var myDiv = $("#div_id").get(0);
myDiv.animate({
scrollTop: myDiv.scrollHeight
}, 500);
I have encountered the same problem, but with an additional constraint: I had no control over the code that appended new elements to the scroll container. None of the examples I found here allowed me to do just that. Here is the solution I ended up with .
It uses Mutation Observers (https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver) which makes it usable only on modern browsers (though polyfills exist)
So basically the code does just that :
var scrollContainer = document.getElementById("myId");
// Define the Mutation Observer
var observer = new MutationObserver(function(mutations) {
// Compute sum of the heights of added Nodes
var newNodesHeight = mutations.reduce(function(sum, mutation) {
return sum + [].slice.call(mutation.addedNodes)
.map(function (node) { return node.scrollHeight || 0; })
.reduce(function(sum, height) {return sum + height});
}, 0);
// Scroll to bottom if it was already scrolled to bottom
if (scrollContainer.clientHeight + scrollContainer.scrollTop + newNodesHeight + 10 >= scrollContainer.scrollHeight) {
scrollContainer.scrollTop = scrollContainer.scrollHeight;
}
});
// Observe the DOM Element
observer.observe(scrollContainer, {childList: true});
I made a fiddle to demonstrate the concept :
https://jsfiddle.net/j17r4bnk/
Found this really helpful, thank you.
For the Angular 1.X folks out there:
angular.module('myApp').controller('myController', ['$scope', '$document',
function($scope, $document) {
var overflowScrollElement = $document[0].getElementById('your_overflow_scroll_div');
overflowScrollElement[0].scrollTop = overflowScrollElement[0].scrollHeight;
}
]);
Just because the wrapping in jQuery elements versus HTML DOM elements gets a little confusing with angular.
Also for a chat application, I found making this assignment after your chats were loaded to be useful, you also might need to slap on short timeout as well.
Like you, I'm building a chat app and want the most recent message to scroll into view. This ultimately worked well for me:
//get the div that contains all the messages
let div = document.getElementById('message-container');
//make the last element (a message) to scroll into view, smoothly!
div.lastElementChild.scrollIntoView({ behavior: 'smooth' });
small addendum: scrolls only, if last line is already visible. if scrolled a tiny bit, leaves the content where it is (attention: not tested with different font sizes. this may need some adjustments inside ">= comparison"):
var objDiv = document.getElementById(id);
var doScroll=objDiv.scrollTop>=(objDiv.scrollHeight-objDiv.clientHeight);
// add new content to div
$('#' + id ).append("new line at end<br>"); // this is jquery!
// doScroll is true, if we the bottom line is already visible
if( doScroll) objDiv.scrollTop = objDiv.scrollHeight;
Just as a bonus snippet. I'm using angular and was trying to scroll a message thread to the bottom when a user selected different conversations with users. In order to make sure that the scroll works after the new data had been loaded into the div with the ng-repeat for messages, just wrap the scroll snippet in a timeout.
$timeout(function(){
var messageThread = document.getElementById('message-thread-div-id');
messageThread.scrollTop = messageThread.scrollHeight;
},0)
That will make sure that the scroll event is fired after the data has been inserted into the DOM.
This will let you scroll all the way down regards the document height
$('html, body').animate({scrollTop:$(document).height()}, 1000);
You can also, using jQuery, attach an animation to html,body of the document via:
$("html,body").animate({scrollTop:$("#div-id")[0].offsetTop}, 1000);
which will result in a smooth scroll to the top of the div with id "div-id".
Scroll to the last element inside the div:
myDiv.scrollTop = myDiv.lastChild.offsetTop
You can use the Element.scrollTo() method.
It can be animated using the built-in browser/OS animation, so it's super smooth.
function scrollToBottom() {
const scrollContainer = document.getElementById('container');
scrollContainer.scrollTo({
top: scrollContainer.scrollHeight,
left: 0,
behavior: 'smooth'
});
}
// initialize dummy content
const scrollContainer = document.getElementById('container');
const numCards = 100;
let contentInnerHtml = '';
for (let i=0; i<numCards; i++) {
contentInnerHtml += `<div class="card mb-2"><div class="card-body">Card ${i + 1}</div></div>`;
}
scrollContainer.innerHTML = contentInnerHtml;
.overflow-y-scroll {
overflow-y: scroll;
}
<link href="https://cdn.jsdelivr.net/npm/bootstrap#4.5.3/dist/css/bootstrap.min.css" rel="stylesheet"/>
<div class="d-flex flex-column vh-100">
<div id="container" class="overflow-y-scroll flex-grow-1"></div>
<div>
<button class="btn btn-primary" onclick="scrollToBottom()">Scroll to bottom</button>
</div>
</div>
Css only:
.scroll-container {
overflow-anchor: none;
}
Makes it so the scroll bar doesn't stay anchored to the top when a child element is added. For example, when new message is added at the bottom of chat, scroll chat to new message.
Why not use simple CSS to do this?
The trick is to use display: flex; and flex-direction: column-reverse;
Here is a working example. https://codepen.io/jimbol/pen/YVJzBg
A very simple method to this is to set the scroll to to the height of the div.
var myDiv = document.getElementById("myDiv");
window.scrollTo(0, myDiv.innerHeight);
On my Angular 6 application I just did this:
postMessage() {
// post functions here
let history = document.getElementById('history')
let interval
interval = setInterval(function() {
history.scrollTop = history.scrollHeight
clearInterval(interval)
}, 1)
}
The clearInterval(interval) function will stop the timer to allow manual scroll top / bottom.
I know this is an old question, but none of these solutions worked out for me. I ended up using offset().top to get the desired results. Here's what I used to gently scroll the screen down to the last message in my chat application:
$("#html, body").stop().animate({
scrollTop: $("#last-message").offset().top
}, 2000);
I hope this helps someone else.
I use the difference between the Y coordinate of the first item div and the Y coordinate of the selected item div. Here is the JavaScript/JQuery code and the html:
function scrollTo(event){
// In my proof of concept, I had a few <button>s with value
// attributes containing strings with id selector expressions
// like "#item1".
let selectItem = $($(event.target).attr('value'));
let selectedDivTop = selectItem.offset().top;
let scrollingDiv = selectItem.parent();
let firstItem = scrollingDiv.children('div').first();
let firstItemTop = firstItem.offset().top;
let newScrollValue = selectedDivTop - firstItemTop;
scrollingDiv.scrollTop(newScrollValue);
}
<div id="scrolling" style="height: 2rem; overflow-y: scroll">
<div id="item1">One</div>
<div id="item2">Two</div>
<div id="item3">Three</div>
<div id="item4">Four</div>
<div id="item5">Five</div>
</div>
I want to do:
$("img").bind('load', function() {
// do stuff
});
But the load event doesn't fire when the image is loaded from cache. The jQuery docs suggest a plugin to fix this, but it doesn't work
If the src is already set, then the event is firing in the cached case, before you even get the event handler bound. To fix this, you can loop through checking and triggering the event based off .complete, like this:
$("img").one("load", function() {
// do stuff
}).each(function() {
if(this.complete) {
$(this).load(); // For jQuery < 3.0
// $(this).trigger('load'); // For jQuery >= 3.0
}
});
Note the change from .bind() to .one() so the event handler doesn't run twice.
Can I suggest that you reload it into a non-DOM image object? If it's cached, this will take no time at all, and the onload will still fire. If it isn't cached, it will fire the onload when the image is loaded, which should be the same time as the DOM version of the image finishes loading.
Javascript:
$(document).ready(function() {
var tmpImg = new Image() ;
tmpImg.src = $('#img').attr('src') ;
tmpImg.onload = function() {
// Run onload code.
} ;
}) ;
Updated (to handle multiple images and with correctly ordered onload attachment):
$(document).ready(function() {
var imageLoaded = function() {
// Run onload code.
}
$('#img').each(function() {
var tmpImg = new Image() ;
tmpImg.onload = imageLoaded ;
tmpImg.src = $(this).attr('src') ;
}) ;
}) ;
My simple solution, it doesn't need any external plugin and for common cases should be enough:
/**
* Trigger a callback when the selected images are loaded:
* #param {String} selector
* #param {Function} callback
*/
var onImgLoad = function(selector, callback){
$(selector).each(function(){
if (this.complete || /*for IE 10-*/ $(this).height() > 0) {
callback.apply(this);
}
else {
$(this).on('load', function(){
callback.apply(this);
});
}
});
};
use it like this:
onImgLoad('img', function(){
// do stuff
});
for example, to fade in your images on load you can do:
$('img').hide();
onImgLoad('img', function(){
$(this).fadeIn(700);
});
Or as alternative, if you prefer a jquery plugin-like approach:
/**
* Trigger a callback when 'this' image is loaded:
* #param {Function} callback
*/
(function($){
$.fn.imgLoad = function(callback) {
return this.each(function() {
if (callback) {
if (this.complete || /*for IE 10-*/ $(this).height() > 0) {
callback.apply(this);
}
else {
$(this).on('load', function(){
callback.apply(this);
});
}
}
});
};
})(jQuery);
and use it in this way:
$('img').imgLoad(function(){
// do stuff
});
for example:
$('img').hide().imgLoad(function(){
$(this).fadeIn(700);
});
Do you really have to do it with jQuery? You can attach the onload event directly to your image as well;
<img src="/path/to/image.jpg" onload="doStuff(this);" />
It will fire every time the image has loaded, from cache or not.
You can also use this code with support for loading error:
$("img").on('load', function() {
// do stuff on success
})
.on('error', function() {
// do stuff on smth wrong (error 404, etc.)
})
.each(function() {
if(this.complete) {
$(this).load();
} else if(this.error) {
$(this).error();
}
});
I just had this problem myself, searched everywhere for a solution that didn't involve killing my cache or downloading a plugin.
I didn't see this thread immediately so I found something else instead which is an interesting fix and (I think) worthy of posting here:
$('.image').load(function(){
// stuff
}).attr('src', 'new_src');
I actually got this idea from the comments here: http://www.witheringtree.com/2009/05/image-load-event-binding-with-ie-using-jquery/
I have no idea why it works but I have tested this on IE7 and where it broke before it now works.
Hope it helps,
Edit
The accepted answer actually explains why:
If the src is already set then the event is firing in the cache cased before you get the event handler bound.
By using jQuery to generate a new image with the image's src, and assigning the load method directly to that, the load method is successfully called when jQuery finishes generating the new image. This is working for me in IE 8, 9 and 10
$('<img />', {
"src": $("#img").attr("src")
}).load(function(){
// Do something
});
A solution I found https://bugs.chromium.org/p/chromium/issues/detail?id=7731#c12
(This code taken directly from the comment)
var photo = document.getElementById('image_id');
var img = new Image();
img.addEventListener('load', myFunction, false);
img.src = 'http://newimgsource.jpg';
photo.src = img.src;
A modification to GUS's example:
$(document).ready(function() {
var tmpImg = new Image() ;
tmpImg.onload = function() {
// Run onload code.
} ;
tmpImg.src = $('#img').attr('src');
})
Set the source before and after the onload.
Just re-add the src argument on a separate line after the img oject is defined. This will trick IE into triggering the lad-event. It is ugly, but it is the simplest workaround I've found so far.
jQuery('<img/>', {
src: url,
id: 'whatever'
})
.load(function() {
})
.appendTo('#someelement');
$('#whatever').attr('src', url); // trigger .load on IE
I can give you a little tip if you want do like this:
<div style="position:relative;width:100px;height:100px">
<img src="loading.jpg" style='position:absolute;width:100px;height:100px;z-index:0'/>
<img onLoad="$(this).fadeIn('normal').siblings('img').fadeOut('normal')" src="picture.jpg" style="display:none;position:absolute;width:100px;height:100px;z-index:1"/>
</div>
If you do that when the browser caches pictures, it's no problem always img shown but loading img under real picture.
I had this problem with IE where the e.target.width would be undefined. The load event would fire but I couldn't get the dimensions of the image in IE (chrome + FF worked).
Turns out you need to look for e.currentTarget.naturalWidth & e.currentTarget.naturalHeight.
Once again, IE does things it's own (more complicated) way.
You can solve your problem using JAIL plugin that also allows you to lazy load images (improving the page performance) and passing the callback as parameter
$('img').asynchImageLoader({callback : function(){...}});
The HTML should look like
<img name="/global/images/sample1.jpg" src="/global/images/blank.gif" width="width" height="height" />
If you want a pure CSS solution, this trick works very well - use the transform object. This also works with images when they're cached or not:
CSS:
.main_container{
position: relative;
width: 500px;
height: 300px;
background-color: #cccccc;
}
.center_horizontally{
position: absolute;
width: 100px;
height: 100px;
background-color: green;
left: 50%;
top: 0;
transform: translate(-50%,0);
}
.center_vertically{
position: absolute;
top: 50%;
left: 0;
width: 100px;
height: 100px;
background-color: blue;
transform: translate(0,-50%);
}
.center{
position: absolute;
top: 50%;
left: 50%;
width: 100px;
height: 100px;
background-color: red;
transform: translate(-50%,-50%);
}
HTML:
<div class="main_container">
<div class="center_horizontally"></div>
<div class="center_vertically"></div>
<div class="center"></div>
</div>
</div
Codepen example
Codepen LESS example
I am trying to add a scroll event which will change the background of a div which also acts as the window background (it has 100% width and height). This is as far as I get. I am not so good at jquery. I have seen tutorials with click event listeners. but applying the same concept , like, returning scroll event as false, gets me nowhere. also I saw a tutorial on SO where the person suggest use of array. but I get pretty confused using arrays (mostly due to syntax).
I know about plugins like waypoints.js and skrollr.js which can be used but I need to change around 50-60 (for the illusion of a video being played when scrolled) ... but it wont be feasible.
here is the code im using:-
*
{
border: 2px solid black;
}
#frame
{
background: url('1.jpg') no-repeat;
height: 1000px;
width: 100%;
}
</style>
<script>
$(function(){
for ( i=0; i = $.scrolltop; i++)
{
$("#frame").attr('src', ''+i+'.jpg');
}
});
</script>
<body>
<div id="frame"></div>
</body>
Inside your for loop, you are setting the src attribute of #frame but it is a div not an img.
So, instead of this:
$("#frame").attr('src', ''+i+'.jpg');
Try this:
$("#frame").css('background-image', 'url(' + i + '.jpg)');
To bind a scroll event to a target element with jQuery:
$('#target').scroll(function() {
//do stuff here
});
To bind a scroll event to the window with jQuery:
$(window).scroll(function () {
//do stuff here
});
Here is the documentation for jQuery .scroll().
UPDATE:
If I understand right, here is a working demo on jsFiddle of what you want to achieve.
CSS:
html, body {
min-height: 1200px; /* for testing the scroll bar */
}
div#frame {
display: block;
position: fixed; /* Set this to fixed to lock that element on the position */
width: 300px;
height: 300px;
z-index: -1; /* Keep the bg frame at the bottom of other elements. */
}
Javascript:
$(document).ready(function() {
switchImage();
});
$(window).scroll(function () {
switchImage();
});
//using images from dummyimages.com for demonstration (300px by 300px)
var images = ["http://dummyimage.com/300x300/000000/fff",
"http://dummyimage.com/300x300/ffcc00/000",
"http://dummyimage.com/300x300/ff0000/000",
"http://dummyimage.com/300x300/ff00cc/000",
"http://dummyimage.com/300x300/ccff00/000"
];
//Gets a valid index from the image array using the scroll-y value as a factor.
function switchImage()
{
var sTop = $(window).scrollTop();
var index = sTop > 0 ? $(document).height() / sTop : 0;
index = Math.round(index) % images.length;
//console.log(index);
$("#frame").css('background-image', 'url(' + images[index] + ')');
}
HTML:
<div id="frame"></div>
Further Suggestions:
I suggest you change the background-image of the body, instead of the div. But, if you have to use a div for this; then you better add a resize event-istener to the window and set/update the height of that div with every resize. The reason is; height:100% does not work as expected in any browser.
I've done this before myself and if I were you I wouldn't use the image as a background, instead use a normal "img" tag prepend it to the top of your page use some css to ensure it stays in the back under all of the other elements. This way you could manipulate the size of the image to fit screen width better. I ran into a lot of issues trying to get the background to size correctly.
Html markup:
<body>
<img src="1.jpg" id="img" />
</body>
Script code:
$(function(){
var topPage = 0, count = 0;
$(window).scroll( function() {
topPage = $(document).scrollTop();
if(topPage > 200) {
// function goes here
$('img').attr('src', ++count +'.jpg');
}
});
});
I'm not totally sure if this is what you're trying to do but basically, when the window is scrolled, you assign the value of the distance to the top of the page, then you can run an if statement to see if you are a certain point. After that just simply change run the function you would like to run.
If you want to supply a range you want the image to change from do something like this, so what will happen is this will allow you to run a function only between the specificied range between 200 and 400 which is the distance from the top of the page.
$(function(){
var topPage = 0, count = 0;
$(window).scroll( function() {
topPage = $(document).scrollTop();
if(topPage > 200 && topPage < 400) {
// function goes here
$('#img').attr('src', ++count +'.jpg');
}
});
});