Develop Reference

Trying to loop a function to run on multiple elements - jQuery

I'm trying to get this jQuery parallax code to work but I don't want to spaghetti everything. How can it be looped to apply to multiple element IDs?
(it doesn't work with classes because the function needs to run multiple times specific to each particular div) - I'm not very good when it comes to looping, still learning how to do this stuff.
Anyway, this is a functioning code for one section (a div with a child div, #about > #pAbout in this instance):
$(document).ready(function() {
if ($("#pAbout").length) {
parallax();
}
});
$(window).scroll(function(e) {
if ($("#pAbout").length) {
parallax();
}
});
function parallax(){
if( $("#pAbout").length > 0 ) {
var plxBackground = $("#pAbout");
var plxWindow = $("#about");
var plxWindowTopToPageTop = $(plxWindow).offset().top;
var windowTopToPageTop = $(window).scrollTop();
var plxWindowTopToWindowTop = plxWindowTopToPageTop - windowTopToPageTop;
var plxBackgroundTopToPageTop = $(plxBackground).offset().top;
var windowInnerHeight = window.innerHeight;
var plxBackgroundTopToWindowTop = plxBackgroundTopToPageTop - windowTopToPageTop;
var plxBackgroundTopToWindowBottom = windowInnerHeight - plxBackgroundTopToWindowTop;
var plxSpeed = 0.35;
plxBackground.css('top', - (plxWindowTopToWindowTop * plxSpeed) + 'px');
}
}
I was hoping to create an array like this:
var ids = ['#pAbout', '#pConcept', '#pBroadcast', '#pDigital', '#pDesign', '#pContact'];
But I can't get the e business to work unfortunately, it's very frustrating for me. Any help would be greatly appreciated!

You can use multiple selector in jQuery to select disparate elements by simply using a comma between the selectors.
$("#pAbout, #pConcept, #pBroadcast, #pDigital, #pDesign, #pContact")
.each(function(){
//manipulate element here
});
That each() iterates over all matched elements so no need to check for length etc.

Prevent javascript search function from slowing down browser

I have a bit of javascript / jquery that upon pressing "enter" in a search box goes through all table rows and then hides those which are not applicable/ do not contain the string. This process is however is extremely taxing on slower systems and so I decided to implement a small loading gif so people know something is happening even though it seems the browser has frozen. The problem though is that the image never appears. I'm assuming it's because the browser freezes. So, now to my question. How can i either make the loop faster, use less computing power, and show the gif? Thank you very much
var $rows = $('tbody tr.visall');
$('#search').keydown(function(e) {
if (e.keyCode == 13){
$('.load').show();
var val = $.trim($(this).val()).replace(/ +/g, ' ').toLowerCase();
$rows.show().filter(function () {
var text = $(this).text().replace(/\s+/g, ' ').toLowerCase();
return !~text.indexOf(val);
}).hide();
};
$('.load').hide();
});
edit: this code goes through about 9000-10000 tr elements.

Hard to say if it will be enough for your data. But here is what you can do:
Reduce the amount of dom manipulations. You can add|remove class hidden to show hide rows.
If your text is static you can create text cache and do not extract it on every search.
You can use setTimeout to delay search execution to show loading gif. Not even sure you will need one. Searching in memory is quite fast.
Demo.
Code
$(function() {
var table = $('#mytable'), //your table
rows = table.find('tr').map(function(){ //all rows you need
return $(this);
}),
rowsCache = (function(from){ //text cache
return from.map(function(){
return this.text();
});
}(rows));
function delay(func) { //delayed function executor
setTimeout(func, 13);
}
var load = $('#load'); //your loader
$('#search').keydown(function(e){
var val;
if(e.keyCode === 13) {
val = $.trim($(this).val());
load.show();
table.hide(); //release dom
delay(function() {
//search in text cache
var toShow = rowsCache.map(function(_, row) {
return row.indexOf(val) > -1;
});
rows.each(function(i){
//simply toggle class let css work for you
this.toggleClass('hidden', !toShow[i]);
});
load.hide();
table.show();
});
}
});
});

Personally I would say drop the filter and use CSS selectors instead then it's just basic DOM manipulation which jQuery should be optimized for.
See http://api.jquery.com/contains-selector/ for documentation and here is a little fiddle http://jsfiddle.net/tgz5X/
Here is what I use in the fiddle as a simple example
function search(mySearchValue) {
$("tr > td:contains(" + mySearchValue + ")").show();
$("tr > td:not(:contains(" + mySearchValue + "))").hide();
}
You would need more but you should get the idea behind this approach.
Or use filter still but with selectors, also this may trigger hide on element which will have show after so more DOM manipualtion
$("tr td").hide().filter(":contains(" + mySearchValue + ")").show();

REGEX - Highlight part over 19 chars

Hi,
I have some text inside div[contenteditable="true"] and I should highlight (span.tooLong) part which goes over the 19 character limit. Content in div may have HTML tags or entities and those should be ignored when counting to 19.
Twitter has similar way to highlight too long tweet:
Examples:
This is text ⇨ This is text
This is just too long text ⇨ This is just too lo<span class="tooLong">ng text</span>
This <b>text</b> has been <i>formatted</i> with HTML ⇨ This <b>text</b> has been <span class="tooLong"><i>formatted</i> with HTML</span>
How can I implement this in JavaScript?
(I want to use regular expressions as much as possible)

Okay... here's some code that I think will work for you, or at least get your started.
Basically, the regex you need to find everything over 19 characters is this:
var extra = content.match(/.{19}(.*)/)[1];
So, I put together a sample document of how you might use this.
Take a look at the DEMO.
Here's the Javascript I'm using (I'm using jQuery for the locators here, but this can easily be modified to use straight Javascript... I just prefer jQuery for stuff like this)...
$(document).ready(function() {
$('#myDiv').keyup(function() {
var content = $('#myDiv').html();
var extra = content.match(/.{19}(.*)/)[1];
$('#extra').html(extra);
var newContent = content.replace(extra, "<span class='highlight'>" + extra + "</span>");
$('#sample').html(newContent);
});
});
Basically, I have three DIVs setup. One for you to enter your text. One to show what characters are over the 19 character limit. And one to show how you might highlight the extra characters.
My code sample does not check for html tags, as there are too many to try and handle... but should give you a great starting point as to how this might work.
NOTE: you can view the complete code I wrote using this link: http://jsbin.com/OnAxULu/1/edit

Here's an answer that uses my Rangy library. It uses the Class Applier and TextRange modules to apply styling on character ranges within the editable content while preserving the selection. It also uses a configurable debounce interval to prevent sluggishness in editor performance. Also, it should work on old IE.
Demo: http://jsfiddle.net/timdown/G4jn7/2/
Sample code:
var characterLimit = 40;
var debounceInterval = 200;
function highlightExcessCharacters() {
// Bookmark selection so we can restore it later
var sel = rangy.getSelection();
var savedSel = sel.saveCharacterRanges(editor);
// Remove previous highlight
var range = rangy.createRange();
range.selectNodeContents(editor);
classApplier.undoToRange(range);
// Store the total number of characters
var editorCharCount = range.text().length;
// Create a range selecting the excess characters
range.selectCharacters(editor, characterLimit, editorCharCount);
// Highlight the excess
classApplier.applyToRange(range);
// Restore the selection
sel.restoreCharacterRanges(editor, savedSel);
}
var handleEditorChangeEvent = (function() {
var timer;
function debouncer() {
if (timer) {
timer = null;
}
highlightExcessCharacters();
}
return function() {
if (timer) {
window.clearTimeout(timer);
}
timer = window.setTimeout(debouncer, debounceInterval);
};
})();
function listen(target, eventName, listener) {
if (target.addEventListener) {
target.addEventListener(eventName, listener, false);
} else if (target.attachEvent) {
target.attachEvent("on" + eventName, listener);
}
}
rangy.init();
var editor = document.getElementById("editor");
var classApplier = rangy.createClassApplier("overrun");
// Set up debounced event handlers
var editEvents = ["input", "keydown", "keypress", "keyup",
"cut", "copy", "paste"];
for (var i = 0, eventName; eventName = editEvents[i++]; ) {
listen(editor, eventName, handleEditorChangeEvent);
}

JQuery If Statement using each value from an array

I am writing a function that will be executed on multiple views of an application, and each view can have up to 50 instances of the same element: '.console'. I need to be able to perform an action every time the viewport scrolls to each instance. I have the following code setting up the variables:
//Create empty array with variable values, up to 50
var console = [];
//Find each instance of ".console" and populate the array with its pixel position.
$('.console').each(function() {
console.push($(this)[0].offsetTop);
});
//Determine the current pixel position of the scroll
var scroll = $(document).scrollTop();
Those variables all work fine and dandy, but after hours of pouring over jquery docs I can't figure the if statement out. Here is what I have that works well for the first item in the array:
if (scroll == console[0]){
$('.container').show();
} else {
$('.container').hide();
}
However, I want it to be anytime the scroll position matches each of the values in that array, hopefully something like this:
if (scroll == console[0-50])
Here is the full chunk as is:
$(document).on('scroll', function(){
//Create empty array with variable values, up to 50
var console = [];
//Find each instance of ".console" and populate the array with its pixel position.
$('.console').each(function() {
console.push($(this)[0].offsetTop);
});
//Determine the current pixel position of the scroll
var scroll = $(document).scrollTop();
//Anytime the scroll matches any of the instances of console, show a div
if (scroll == console[0]){
$('.container').show();
} else {
$('.container').hide();
}
});
Any help would be appreciated. I am pretty new to Javascript/JQuery so if I'm approaching the problem in the wrong way altogether, please let me know. Thanks!

Since you said it works for the first one, I'm guessing this may work.
// cache the container
var container = $('.container');
$(document).on('scroll', function(){
//Determine the current pixel position of the scroll
var scroll = $(document).scrollTop();
//Create empty array with variable values, up to 50
var console = [];
//Find each instance of ".console" and populate the array with its pixel position.
$('.console').each(function(index) {
console.push($(this)[0].offsetTop);
if (scroll == console[index]){
$(container).show();
} else {
$(container).hide();
}
});
});

You may wish to take a look at Waypoints. It's a jQuery plugin that is well suited for what you're trying to accomplish.
I whipped up a quick jsFiddle to show it in action: http://jsfiddle.net/dmillz/4xqMb/
$(".console").waypoint(function(direction) {
// Hide or show your ".container" object
});
More Waypoint examples: http://imakewebthings.com/jquery-waypoints/#get-started

Hopefully I understand your problem, which is as follows:
You have a bunch of elements with the .console class, and you want to appear as soon as they are in the viewport. When these elements aren't in the viewport you want them to dissapear?
Since you're interested in when these objects with the .console class are in the viewport, I suggest using this jQuery plugin
http://plugins.jquery.com/appear/
https://github.com/morr/jquery.appear
I suggest wrapping each of the .console objects in a container with another class, and then as these containers appear and disappear show and hide them.
At document ready just do the following:
$(document).ready(function() {
$('<.container-class>').appear();
$('<.container-class>').on('appear', function() { $(this).find('.console').show(); });
$('<.container-class>').on('disappear', function() { $(this).find('.console').hide(); });
});

To answer the question, you could do this:
var cons = $.map($('.console'), function(el) {
return $(el).offset().top;
});
$(document).on('scroll', function(){
var scroll = $(window).scrollTop();
$('.container').toggle( $.inArray(scroll, cons) != -1 );
});
But creating something for a range, considering the height of each element, the height of the window etc. would be a lot more involved.

While the problem was solved via another answer, figuring out how to perform a loop for each value in the array wasn't really solved ... UNTIL NOW!
This is probably a really gross and bloated way to do it, but if you essentially count how many items are in the array, you can then run a loop that many times, putting in the index for each value in the array. Code below:
//Create empty array with variable values
var console = [];
//Find each instance of ".console" and populate the array with its pixel position.
$('.console').each(function() {
console.push($(this)[0].offsetTop);
});
//Count the number of items in the array
var consoleIndex = console.length - 1;
$(document).on('scroll', function(){
//Determine the current pixel position of the scroll
var scroll = $(document).scrollTop();
//Anytime the scroll matches any of the instances of console, show a div
for (var i = 0; i <= consoleIndex; i++) {
if (scroll = console[i]) {
$('.container').toggle();
}
}
});

confusion in jquery parents selector with hasClass function

var allChecked = $('.inboxCheckbox:checked');
if(allChecked.length > 0){
var messageIds = new Array();
var parentRow = null;
allChecked.each(
function(){
parentRow = $(this).parents('tr');
if(!(parentRow.hasClass('gradeA'))){
parentRow.addClass('gradeA');
increaseUnreadMessage();
}
parentRow = null;
messageIds.push($(this).val());
}
);
}else{
showInsMessage('<b class="redTxt">Please Select At Least One Message</b>');
}
i have multiple rows with once checkbox in each row... i was trying to add class gradeA to each row if checkbox is checked.... i do not want to call addClass if it already has class gradeA.... when i select multiple rows then it adds class to only one row. does that mean
lets say i have three rows with checkbox in each row and i select each checkbox when i run
$(':checked').each(
$(this).parents('tr')
)does it select all the rows with checked boxes or only the specfic parent row.... my assuption was it only gives the specific parent row..... if it gives specific row then it should work .. but once i add a class to parent row and move to another row then parentRow.hasClass('gradeA') return true... i am confused now if it checks all the row with checkboxes then is there any way to select specific parent row......
Thanks for reading

Would be nice to see the markup, are there more tables nested?
However,
parentRow = $(this).closest('tr');
should be a better choice.

API says that .parents() method search through all ancestors of the elements.
.parent() travels only a single level up the DOM tree.
If your checkbox is a direct child (not a deep descendant) of 'tr' then you can try
parentRow = $(this).parent('tr');

Your code should work. I suspect that the problem is happening because your function increaseUnreadMessage() is throwing an error, which is causing the rest of the each() loop to be skipped.
But, to answer your specific question: yes, you can select all rows (<td>s) that contain checked checkboxes. Using jquery's :has selector, like this:
var allCheckedRows = $('tr:has(.inboxCheckbox:checked)');
from there, of course, you can just use addClass() to apply your classname to all of them:
allCheckedRows.addClass('gradeA');
of course, you've got other things going on in your each() loop, so you probably can't throw out the each() entirely. As I said above, your code works... but something like this might be cleaner, and easier to understand.
var messageIds = new Array();
var allCheckedRows = $('tr:has(.inboxCheckbox:checked)');
allCheckedRows.addClass('gradeA');
allCheckedRows.find('.inboxCheckbox').each( function() {
var cb = $(this);
increaseUnreadMessage();
messageIds.push( cb.val() );
});
if( messageIds.length === 0 ) {
showInsMessage('<b class="redTxt">Please Select At Least One Message</b>');
}

BTW, I think you can do it more jQuerish style :
var messageIds = [];
$('tr.youTrs').toggleClass('gradeA', function () {
var checkbox = $(this).find('.inboxCheckbox');
if (checkbox.is(':checked')){
messageIds.push(checkbox.val());
return true;
}
else{
showInsMessage('<b class="redTxt">Please Select At Least One Message</b>');
return false;
}
});