Some Useful JavaScript & jQuery Snippets

$(imageobj).attr('src', $(imageobj)
           .attr('src') + '?' + Math.random() );

var imgsrc = 'img/image1.png';
$('<img/>').load(function () {
    alert('image loaded');
}).error(function () {
    alert('error loading image');
}).attr('src', imgsrc);

var totalimages  = 10;
var loadedimages = 0;
$("<img/>").load(function() {
    ++loadedimages;
    if(loadedimages == totalimages){
        //All 10 images are loaded
    }
});

clearSelection      : function () {
    if(document.selection && document.selection.empty) {
        document.selection.empty();
    } else if(window.getSelection) {
        var sel = window.getSelection();
        sel.removeAllRanges();
    }
}
$(element).bind('dblclick',function(event){
    //do something
    clearSelection();
});

var email = 'info@tympanus.net'
if(!(/^((([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(\.([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+)*)|((\x22)((((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(([\x01-\x08\x0b\x0c\x0e-\x1f\x7f]|\x21|[\x23-\x5b]|[\x5d-\x7e]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(\\([\x01-\x09\x0b\x0c\x0d-\x7f]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))))*(((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(\x22)))@((([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.)+(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.?$/i.test(email)))
alert('Invalid Email');

<ul>
<li>cloud</li>
<li>sun</li>
<li>rain</li>
<li>snow</li>
</ul

var items = $('.to_order li').get();
items.sort(function(a,b){
    var keyA = $(a).text();
    var keyB = $(b).text();

    if (keyA < keyB) return -1;
    if (keyA > keyB) return 1;
    return 0;
});
var ul = $('.to_order');
$.each(items, function(i, li){
    ul.append(li);
});

timeout = setTimeout(function(){myFunction(param)},time);

$(document).ready(function(){
    $(document).bind("contextmenu",function(e){
        return false;
    });
});

$('imageelement').fadeOut(function() {
    $(this).load(function() {
        $(this).fadeIn();
    }).attr('src', AnotherSource);
});

//extend the jQuery functionality
$.extend($.expr[':'], {

    //name of your special selector
    moreThanAThousand : function (a){
        //Matching element
        return parseInt($(a).html()) > 1000;
    }
});

$(document).ready(function() {
    $('td:moreThanAThousand').css('background-color', '#ff0000');
});

var count = 0;
function myFunction() {
    count++;
    if(count > 5) clearInterval(timeout);
    //do something
}
var timeout = setInterval(myFunction, 20000);

if ($("#elementid").length) {
    //it does!
}

var req = $.ajax({
type:     "POST",
url:     "someurl",
data:     "id=1",
success: function(){
//something
}
});
//Cancel the Ajax Request
req.abort()