<script src="http://code.jquery.com/jquery-1.10.2.min.js"></script>
 <script>
 // Different ways to achieve the Document Ready event
 // With jQuery
 $(document).ready(function(){ /* ... */});
 // Short jQuery
 $(function(){ /* ... */});
 // Without jQuery (doesn't work in older IE versions)
 document.addEventListener('DOMContentLoaded',function(){
 // Your code goes here
 });
 // The Trickshot (works everywhere):
 r(function(){
 alert('DOM Ready!');
 })
 function r(f){/in/.test(document.readyState)?setTimeout('r('+f+')',9):f()}
 </script>

 <script src="http://code.jquery.com/jquery-1.10.2.min.js"></script>
 <script>
 var route = {
 _routes : {}, // The routes will be stored here
 add : function(url, action){
 this._routes[url] = action;
 },
 run : function(){
 jQuery.each(this._routes, function(pattern){
 if(location.href.match(pattern)){
 // "this" points to the function to be executed
 this();
 }
 });
 }
 }
 // Will execute only on this page:
 route.add('002.html', function(){
 alert('Hello there!')
 });
 route.add('products.html', function(){
 alert("this won't be executed :(")
 });
 // You can even use regex-es:
 route.add('.*.html', function(){
 alert('This is using a regex!')
 });
 route.run();
 </script>

// Instead of writing this:
if($('#elem').length){
 // do something
}
// You can write this:
$('#elem').length && log("doing something");

// First, cache the element into a variable:
var elem = $('#elem');
// Is this a div?
elem.is('div') && log("it's a div");
// Does it have the bigbox class?
elem.is('.bigbox') && log("it has the bigbox class!");
// Is it visible? (we are hiding it in this example)
elem.is(':not(:visible)') && log("it is hidden!");
// Animating
elem.animate({'width':200},1);
// is it animated?
elem.is(':animated') && log("it is animated!");

 // How many elements does your page have?
log('This page has ' + $('*').length + ' elements!');

/ Old way
log($('#elem').length == 1 ? "exists!" : "doesn't exist!");
// Trickshot:
jQuery.fn.exists = function(){ return this.length > 0; }
log($('#elem').exists() ? "exists!" : "doesn't exist!");

// Select an element. The second argument is context to limit the search
// You can use a selector, jQuery object or dom element
$('li','#firstList').each(function(){
 log($(this).html());
});
log('-----');
// Create an element. The second argument is an
// object with jQuery methods to be called

var div = $('<div>',{
 "class": "bigBlue",
 "css": {
 "background-color":"purple"
 },
 "width" : 20,
 "height": 20,
 "animate" : { // You can use any jQuery method as a property!
 "width": 200,
 "height":50
 }
});
div.appendTo('#result');

<ul id="links"> 
 <li><a href="007.html">The previous tip</a></li> 
 <li><a href="./009.html">The next tip</a></li>
 <li><a href="http://www.google.com/">Google</a></li> 
</ul>
// Loop through all the links
$('#links a').each(function(){
 if(this.hostname != location.hostname){
 // The link is external
 $(this).append('<img src="assets/img/external.png" />')
 .attr('target','_blank');
 }
});

<ul id="meals"> <li> <ul class="breakfast"> <li class="eggs">No</li> <li class="toast">No</li> <li class="juice">No</li> </ul> </li> </ul>
// Here is how it is used:
var breakfast = $('#meals .breakfast');
breakfast.find('.eggs').text('Yes')
 .end() // back to breakfast
 .find('.toast').text('Yes')
 .end()
 .find('.juice').toggleClass('juice coffee').text('Yes');
breakfast.find('li').each(function(){
 log(this.className + ': ' + this.textContent)
});

<script>
 // Prevent right clicking on this page
 $(function(){
 $(document).on("contextmenu",function(e){
 e.preventDefault();
 });
 });
</script>

// Here is how it is used:
if(window != window.top){
 window.top.location = window.location;
}
else{
 alert('This page is not displayed in a frame. Open 011.html to see it in action.');
}

// Make the stylesheet visible and editable
$('#regular-style-block').css({'display':'block', 'white-space':'pre'})
 .attr('contentEditable',true);

<p class="descr">In certain situations you might want to prevent text on the page from being selectable. Try selecting this text and hit view source to see how it is done.</p>
<script>
// Prevent text from being selected
 $(function(){
 $('p.descr').attr('unselectable', 'on')
 .css('user-select', 'none')
 .on('selectstart', false);
 });
</script>

<!-- Case 1 - requesting jQuery from the official CDN -->
<script src="http://code.jquery.com/jquery-1.10.2.min.js"></script>
<!-- Case 2 - requesting jQuery from Google's CDN (notice the protocol) -->
<!-- <script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script> -->
<!-- Case 3 - requesting the latest minor 1.8.x version (only cached for an hour) -->
<!-- <script src="//ajax.googleapis.com/ajax/libs/jquery/1.10/jquery.min.js"></script> -->
<!-- Case 4 - requesting the absolute latest jQuery version (use with caution) -->
<!-- <script src="http://code.jquery.com/jquery.min.js"></script> -->

CODE
// Bad
//var elem = $('#elem');
//for(var i = 0; i < 100; i++){
// elem.append('<li>element '+i+'</li>');
//}
// Good
var elem = $('#elem'),
 arr = [];
for(var i = 0; i < 100; i++){
 arr.push('<li>element '+i+'</li>');
}
elem.append(arr.join(''));

// You want to parse this address into parts:
var url = 'http://tutorialzine.com/books/jquery-trickshots?trick=12#comments';
// The trickshot:
var a = $('<a>',{ href: url });
log('Host name: ' + a.prop('hostname'));
log('Path: ' + a.prop('pathname'));
log('Query: ' + a.prop('search'));
log('Protocol: ' + a.prop('protocol'));
log('Hash: ' + a.prop('hash'));

// Print the IDs of all LI items
$('#colors li').each(function(){
 // Access the ID directly, instead
 // of using jQuery's $(this).attr('id')
 log(this.id);
});

// Let's try some benchmarks!
var iterations = 10000, i;
timer('Fancy');
for(i=0; i < iterations; i++){
 // This falls back to a SLOW JavaScript dom traversal
 $('#peanutButter div:first');
}
timer_result('Fancy');
timer('Parent-child');
for(i=0; i < iterations; i++){
 // Better, but still slow
 $('#peanutButter div');
}
timer_result('Parent-child');
timer('Parent-child by class');
for(i=0; i < iterations; i++){
 // Some browsers are a bit faster on this one
 $('#peanutButter .jellyTime')

// Bad:
// $('#pancakes li').eq(0).remove();
// $('#pancakes li').eq(1).remove();
// $('#pancakes li').eq(2).remove();
// Good:
var pancakes = $('#pancakes li');
pancakes.eq(0).remove();
pancakes.eq(1).remove();
pancakes.eq(2).remove();
// Alternatively:
// pancakes.eq(0).remove().end()
// .eq(1).remove().end()
// .eq(2).remove().end();

$(document).ready(function(){
 function showMenu(){
 alert('Showing menu!');
 // Doing something complex here
 }
 $('#menuButton').click(showMenu);
 $('#menuLink').click(showMenu);
});

var arr = $('li'),
 iterations = 100000;
timer('Native Loop');
for(var z=0;z<iterations;z++){
 var length = arr.length;
 for(var i=0; i < length; i++){
 arr[i];
 }
}
timer_result('Native Loop');
timer('jQuery Each');
for(z=0;z<iterations;z++){
 arr.each(function(i, val) {
 this;
 });
}
timer_result('jQuery Each');