I'm new to javascript (and I'm not allowed to use jQuery in class) and I'm struggling with onclick functions.
I want two separate sentences to turn green and the other one pink when I click on it so I gave both of them a different id.
for(var i = 0; i < content.length; i++){
var contentText = content[i];
var opening = document.createElement("p");
opening.id = "opening";
if(content[i].id ==="opening"){
opening.innerText = contentText.text;
}
textContainer1.append(opening);
document.getElementById("opening").onclick = function opening(){
document.getElementById("opening").style.color = 'green';
}
This is the first onclick function and it works like it should! But when I add the other sentence underneath:
for(var j = 0; j < content.length; j++){
var contentText2 = content[j];
var second = document.createElement("p");
second.className = "chapter-1";
second.id = "second";
if (content[j].id ==="second"){
second.innerText = contentText2.text;
}
textContainer2.append(second);
}
document.getElementById("second").onclick = function second(){
document.getElementById("second").style.color = 'pink';
}
The second one doesn't work anymore. I really can't figure out how to solve this and I need several ones in the same file. Can someone please help?
EDIT
I found out that it only works for the first thing in the json list, and not for the second, or third, etc. So I think I need a for loop to search within the elements, but I'm not sure how to do that in this case...
New answer
I think you've missed a } in the first bit of code.
for(var i = 0; i < content.length; i++){
var contentText = content[i];
var opening = document.createElement("p");
opening.id = "opening";
if(content[i].id ==="opening"){
opening.innerText = contentText.text;
}
textContainer1.append(opening);
}
document.getElementById("opening").onclick = function opening(){
document.getElementById("opening").style.color = 'green';
}
Old answer with probably better code
I may be misunderstanding you, but if you want your sentences to go green/pink when clicking on them, you just need the second function in each of your examples.
<p id="opening" onclick="opening();">opening</p>
<p id="second" onclick="second();">second</p>
<script>
var opening = function() {
document.getElementById("opening").style.color = "green";
}
var second = function() {
document.getElementById("second").style.color = "pink";
}
</script>
This makes opening go green when one clicks it and second go pink when one clicks it.
Alternatively, if you want to assign it without adding onclick in HTML:
document.getElementById("opening").onclick = function() {
document.getElementById("opening").style.color = "green";
}
document.getElementById("second").onclick = function() {
document.getElementById("second").style.color = "pink";
}
Related
I'm trying to learn JS and this is my little app.
Every time I press the "INSTANTIATE" button, it instantiates a tomatoe.png in my <div>.
When the user reloads the page, the tomatoe.png should appear as many times as they've pressed the "INSTANTIATE" button.
This is the code. For this purpose, I created a variable (i), and it increments on every button press.
I planned to save this variable into localStorage, and when the page gets reloaded, I want to call a loop function that instantiates the tomatoe.png i times.
function popUp() {
var img = document.createElement("img");
img.src = "tomato.png";
var src = document.getElementById("header");
src.appendChild(img);
i++;
localStorage.setItem("apples", i);
}
<button onclick="popUp()">INSTANTIATE</button>
<div id="header"></div>
So, when the user reloads the page, as many tomatoes should appear as many times they've pressed the button.
I think I have to use a loop, but I don't know how.
Just get the item in localStorage and loop until it reaches 0, creating a new image each time (localStorage don't works in StackOverflow snippets here because of security reasons, but you get the point).
var i = 0;
function popUp() {
newImage();
i++;
localStorage.setItem("apples", i);
}
function newImage() {
var img = document.createElement("img");
img.src = "tomato.png";
var src = document.getElementById("header");
src.appendChild(img);
}
var oldi = Number(localStorage.getItem("apples"));
while (oldi > 0) {
oldi--;
newImage();
}
<button onclick="popUp()">INSTANTIATE</button>
<div id="header"></div>
First of all, you have to declare i outside your function (in case you haven't done it already) and give it a value of zero, if it isn't exist in the Local Storage:
let i = localStorage.getItem("apples") || 0;
Then, create a loop, that loops i times:
for(let n = 0; n < i; n++){}
And finally, just create tomatoes:
const img = document.createElement("img");
img.src = "tomato.png";
const src = document.getElementById("header");
src.appendChild(img);
So, the full code should look like this:
document.addEventListener('DOMContentLoaded', function(){
function popUp() {
createTomato()
i++;
localStorage.setItem("apples", i);
}
function createTomato() {
const img = document.createElement("img");
img.src = "tomato.png";
const src = document.getElementById("header");
src.appendChild(img);
}
document.getElementById("instantiate").addEventListener("click", popUp)
let i = localStorage.getItem("apples") || 0;
for (let n = 0; n < i; n++) createTomato();
})
<button id="instantiate">INSTANTIATE</button>
<div id="header"></div>
Try it on codepen.io
I'm quite new to coding and functions etc.
I've decided to look for online exam papers so I can learn from them questions and one of them says:
Write a line of code that could be added to the end of the showpic function that updates the alt attribute on the placehold element.
and then there is a long coding which is:
window.onload = prepareGallery;
function prepareGallery() {
var gallery, links, i;
if (!document.getElementById) {
return false;
}
if (!document.getElementsByTagName) {
return false;
}
gallery = document.getElementById("images");
links = gallery.getElementsByTagName("a");
for(i = 0; i < links.length; i++) {
links[i].onclick = function() {
showPic(this);
return false;
}
}
}
function showPic(pic) {
var source, placehold, text, desc;
source = pic.getAttribute("href");
placehold = document.getElementById("place");
placehold.setAttribute("src", source);
text = pic.getAttribute("title");
desc = document.getElementById("description");
desc.firstChild.nodeValue = text;
}
It'd be
pic.setAttribute("alt", "image");
Given that the pic argument is a representation of an <img></img> tag
setAttribute takes two arguments: The first is the tag name (in your case - the alt tag) and the second argument is the value.
I would like to let there automatically appear text inside an input type=text element.
I would like to accomplish that the different kind of texts are stored inside an array and that every 5 seconds or so, a text is 'typed' by javascript into this field. Then I also like that when I focus on the field (to input text in it by keyboard) that it stops auto-typing and shows an empty input element.
Anybody know how to go about this?
I'm a back-end programmer, but need to do some frontend programming and just haven't had the time to thoroughly learn Javascript. At the moment I only know PHP thoroughly, but would expand my knowledge to css, html and javascript too.
Hope somebody is able to help me out :)
EDIT: This is the solution I came up with and it works. The input field has as ID: searchBar. The code is not very elegant, but I'm still learning :) Thanks for the answers. It helped me a lot.
var searchBar = document.getElementById('searchBar');
var keywords = ['Auto typed text number 1',
'This is number 2 auto typed',
'Yet another auto typed line',
'The last line before it loops again'];
var index = 0;
var arrCounter = 0;
var focus = false;
var timer1, timer2;
function resetBox() {
searchBar.value = '';
index = 0;
autoType();
}
var autoType = function() {
if (focus) {
return;
}
if (index <= keywords[arrCounter].length) {
searchBar.value = keywords[arrCounter].substr(0, index++);
timer1 = setTimeout("autoType()", 50);
} else {
arrCounter++;
if(arrCounter === keywords.length){
arrCounter = 0;
}
timer2 = setTimeout(resetBox, 5000);
}
};
autoType();
$("#searchBar").on("focus", function(){
focus = true;
searchBar.value = '';
clearTimeout(timer1);
clearTimeout(timer2);
}).on("blur", function(){
setTimeout(function() {
focus = false;
resetBox();
}, 1000);
});
Try like this:
html
<input id='demo_input' size='100'/>
javascript:
var demo_input = document.getElementById('demo_input');
var type_this = "try this example";
var index = 0;
window.next_letter = function() {
if (index <= type_this.length) {
demo_input.value = type_this.substr(0, index++);
setTimeout("next_letter()", 50);
}
}
next_letter();
Yes, I've searched high and low on Stack Overflow and seen some great solutions to this problem that's been solved time and time again with things like SimpleModal, jQuery.confirm and the like.
Problem is, I am developing for this low level device that doesn't allow for a JS framework to be utilized AND I am having to shoehorn this modal confirm into existing JS.
There is an existing script that I am at liberty to edit (but not rewrite) that does a few things like validate, concatenate a few inputs into a single variable, and more.
The script was written to:
Take some session variables and assign new variable names to them and format accordingly
Present a confirm to the user to see whether they want to use those variables to pre-populate the form on the page
Get some functions ready to validate inputs.
other stuff, like offer an abandonment scenario, among other things
Now, all was good when the "confirm" was in place as the script would pause until an OK or Cancel was provided. I am now presenting a modal on the page that I want to mock this behavior and the only way I can think of doing it is to remove that reliance on the line that goes through the confirm thing and NOT run the script until the user interacts with the modal.
Does anyone have an idea how to take what's in place and "wrap" it in a "listening" if/else scenario for each of the YES or NO possibilities?
Sorry if this is jumbled... my brain is all blended up at the moment, too.
As far as I know there is - so far - no way to halt scripts like the Browser specific alert() or confirm() Dialog does.
Frameworks like dojo for example try to mock this behaviour by putting a transparent DIV over the whole window to prevent clicks or other input while the Dialog is showing.
This is quite tricky as I have experienced, since Keyboard-Input may be able to activate Input Fields or Buttons behind this curtain. Keyboard Shortcuts or Field-Tabbing for example.
One sollution is to disable active Elements manually, which works quite well with me in most cases.
One or more function is passed to this "mock" Dialog to execute when an option was chosen.
Escpecially with ajax background activity the responsibilty to stop conflicting function calls while the Dialog is open lies with the developer.
Here is an example I came up with:
<html>
<head>
<title>Modal Dialog example</title>
<script type="text/javascript">
<!--
var ModalDialog = function(text,choices){
this._text = text;
this._choices = choices;
this._panel = null;
this._modalDialog = null;
this._disableElements = function(tag){
var elements = document.getElementsByTagName(tag);
for(i=0; i < elements.length; i++){
elements[i].disabled = true;
}
};
this._enableElements = function(tag){
var elements = document.getElementsByTagName(tag);
for(i=0; i < elements.length; i++){
elements[i].disabled = false;
}
};
this._disableBackground = function(){
if(this._panel){
this._panel.style.display = 'block';
}
else{
// lower the curtain
this._panel = document.createElement('div');
this._panel.style.position = 'fixed';
this._panel.style.top = 0;
this._panel.style.left = 0;
this._panel.style.backgroundColor = 'gray';
this._panel.style.opacity = '0.2';
this._panel.style.zIndex = 99; // make sure the curtain is in front existing Elements
this._panel.style.width = '100%';
this._panel.style.height = '100%';
document.body.appendChild(this._panel);
// Disable active Elements behind the curtain
this._disableElements('INPUT');
this._disableElements('BUTTON');
this._disableElements('SELECT');
this._disableElements('TEXTAREA');
}
};
this.close = function(){
// Hide Curtain
this._panel.style.display = 'none';
// Hide Dialog for later reuse - could also be removed completely
this._modalDialog.style.display = 'none';
// reactivate disabled Elements
this._enableElements('INPUT');
this._enableElements('BUTTON');
this._enableElements('SELECT');
this._enableElements('TEXTAREA');
};
this.open = function(){
var _this = this;
this._disableBackground();
if(this._modalDialog){
this._modalDialog.style.display = 'block';
}
else{
// create the Dialog
this._modalDialog = document.createElement('div');
this._modalDialog.style.position = 'absolute';
this._modalDialog.style.backgroundColor = 'white';
this._modalDialog.style.border = '1px solid black';
this._modalDialog.style.padding = '10px';
this._modalDialog.style.top = '40%';
this._modalDialog.style.left = '30%';
this._modalDialog.style.zIndex = 100; // make sure the Dialog is in front of the curtain
var dialogText = document.createElement('div');
dialogText.appendChild(document.createTextNode(this._text));
// add Choice Buttons to the Dialog
var dialogChoices = document.createElement('div');
for(i = 0; i < this._choices.length; i++){
var choiceButton = document.createElement('button');
choiceButton.innerHTML = this._choices[i].label;
var choiceAction = _this._choices[i].action
var clickAction = function(){
_this.close();
if(choiceAction)choiceAction();
};
choiceButton.onclick = clickAction;
dialogChoices.appendChild(choiceButton);
}
this._modalDialog.appendChild(dialogText);
this._modalDialog.appendChild(dialogChoices);
document.body.appendChild(this._modalDialog);
}
};
};
var myConfirm = function(text,okAction){
var dialog = new ModalDialog(text,[
{
label:'ok',
action : function(){
console.log('ok')
okAction();
}
},
{
label:'cancel'
}
]);
dialog.open();
};
-->
</script>
</head>
<body>
<form name="identity" action="saveIdentity.do">
<label>Firstname</label><input name="name" type="text"><br>
<label>Lastname</label><input name="name" type="text"><br>
<input type="button"
value="submit"
onclick="if(myConfirm('Do you really want to Commit?',function(){ document.forms['identity'].submit();}));">
</form>
</body>
</html>
In this code there is still an error concerning the availability of the stored choice-function (undefined) at execution time. The function variable is no longer available in the closure. If anyone has a sollution for this you are welcome to add to it.
Hope that comes near to what you need to know.
Updated version: fixed choiceAction undefined, added IE compatibility. Internet Explorer is one main reason to use this, since confirm() is now blocked by default.
<!doctype html>
<html><head>
<title>Modal Dialog example</title>
<script type="text/javascript"><!-- //http://stackoverflow.com/questions/4739740/yet-another-confirm-replacement-quesiton
var ModalDialog = function(text,choices) {
this._text = text;
this._choices = choices;
this._panel = null;
this._modalDialog = null;
this._disableElements = function(tag) {
var elements = document.getElementsByTagName(tag);
for(i=0; i < elements.length; i++) {
elements[i].disabled = true;
}
};
this._enableElements = function(tag) {
var elements = document.getElementsByTagName(tag);
for(i=0; i < elements.length; i++) {
elements[i].disabled = false;
}
};
this._disableBackground = function() {
if(this._panel) {
this._panel.style.display = 'block';
}
else {
// lower the curtain
this._panel = document.createElement('div');
this._panel.style.position = 'fixed';
this._panel.style.top = 0;
this._panel.style.left = 0;
this._panel.style.backgroundColor = '#000';
this._panel.style.opacity = '0.3';
this._panel.style.filter = 'alpha(opacity=30)'; //ie7+
this._panel.style.zIndex = 99; // make sure the curtain is in front existing Elements
this._panel.style.width = '100%';
this._panel.style.height = '100%';
document.body.appendChild(this._panel);
// Disable active Elements behind the curtain
this._disableElements('INPUT');
this._disableElements('BUTTON');
this._disableElements('SELECT');
this._disableElements('TEXTAREA');
}
};
this.close = function() {
// Hide Curtain
this._panel.style.display = 'none';
// Hide Dialog for later reuse - could also be removed completely
this._modalDialog.style.display = 'none';
// reactivate disabled Elements
this._enableElements('INPUT');
this._enableElements('BUTTON');
this._enableElements('SELECT');
this._enableElements('TEXTAREA');
};
this.open = function() {
var _this = this;
this._disableBackground();
if(this._modalDialog) {
this._modalDialog.style.display = 'block';
}
else {
// create the Dialog
this._modalDialog = document.createElement('div');
this._modalDialog.style.position = 'absolute';
this._modalDialog.style.backgroundColor = 'white';
this._modalDialog.style.border = '1px solid black';
this._modalDialog.style.padding = '16px';
this._modalDialog.style.top = '35%';
this._modalDialog.style.left = '30%';
this._modalDialog.style.zIndex = 100; // make sure the Dialog is in front of the curtain
var dialogText = document.createElement('div');
dialogText.style.padding = '0 10px 10px 0';
dialogText.style.fontFamily = 'Arial,sans-serif';
dialogText.appendChild(document.createTextNode(this._text));
// add Choice Buttons to the Dialog
var dialogChoices = document.createElement('div');
for(i = 0; i < this._choices.length; i++) {
var choiceButton = document.createElement('button');
choiceButton.style.marginRight = '8px';
choiceButton.name = i;
choiceButton.innerHTML = this._choices[i].label;
var clickAction = function() {
_this.close();
if(_this._choices[this.name].action) _this._choices[this.name].action();
};
choiceButton.onclick = clickAction;
dialogChoices.appendChild(choiceButton);
}
this._modalDialog.appendChild(dialogText);
this._modalDialog.appendChild(dialogChoices);
document.body.appendChild(this._modalDialog);
}
};
};
var myConfirm = function(text,okAction){
var dialog = new ModalDialog(text,[
{
label : 'OK',
action : function() {
console.log('ok');
okAction();
}
},
{
label : 'Cancel'
}
]);
dialog.open();
};
-->
</script>
</head>
<body>
<form name="identity" action="saveIdentity.do">
<label>Firstname</label><input name="name" type="text"><br>
<label>Lastname</label><input name="name" type="text"><br>
<input type="button" value="submit"
onclick="if(myConfirm('Do you really want to Commit?',function(){ alert('submitted') }));">
<!-- document.forms['identity'].submit(); -->
</form>
</body>
</html>
In javascript I have a reference to a div. In that div is an anchor element with a name='foundItem'
How do I get a reference to the anchor with the name foundItem which is in the Div I have the reference of?
There are 'many' foundItem anchors in other divs on the page. I need 'this' DIVs one.
// assuming you're not using jquery or mootools
// assume div is mydiv
var lst = mydiv.getElementsByTagName('a');
var myanchor;
for(var i=0; i<lst.length; ++i) {
if(lst[i].name && lst[i].name == 'foundItem') {
myanchor = lst[i];
break;
}
}
// the mootools method
var myanchor = $(mydiv).getElement('a[name=foundItem]');
You can use the getElementsByTagName method to get the anchor elements in the div, then look for the one with the correct name attribute:
var found = null;
var e = divReference.getElementsByTagName('A');
for (var i=0; i < e.length; i++) {
if (e[i].name && e[i].name == 'foundItem') {
found = e[i];
break;
}
}
If found is not null, you got the element.
If you happen to use the jQuery library, you can let it do the searching:
var found = null;
var e = $(divReference).find('a[name=foundItem]');
if (e.length == 1) found = e.get(0);
Use a JavaScript library like jQuery and save yourself time.
var theAnchor = $('#divId a[name=foundItem]');
Using jquery, it's dead easy:
<script type="text/javascript">
$(function(){
var item = $("#yourDivId a[name=foundItem]")
)};
</script>
Update:
As per the comments, if you have control over what to id/name/class your anchor tag/s, it would be best to apply a class to them:
<div id="firstDiv">
test
</div>
<div id="secondDiv">
test another one
</div>
<!-- and so forth -->
<script type="text/javascript">
$(function(){
var item = $("#firstDiv a.foundItem");
alert(item.html()); // Will result in "test"
var item2 = $("#secondDiv a.foundItem");
alert(item2.html()); // Will show "test another one"
)};
</script>
If you're doing anything with javascript, jQuery saves you tons of time and is worth investing the effort to learn well. Start with http://api.jquery.com/browser/ to get an intro to what's possible.
Not sure if this helps, but wanted a function to handle the load of a page dynamically and scroll to the anchor of choice.
function scrollToAnchor(anchor_val) {
alert("" + anchor_val);
var page = document.getElementById('tables');
var found = null;
var cnt = 0;
var e = document.getElementsByTagName('a');
for (var i = 0; i < e.length; i++) {
if (e[i].name && e[i].name == anchor_val) {
found = e[i];
break;
}
cnt++;
}
if (found) {
var nPos = found.offsetTop;
alert("" + nPos);
page.scrollBy(0, nPos);
} else {
alert('Failed with call of scrollToAnchor()' + cnt);
}
}