在其他地方你学不到的jQuery小贴士和技巧(欢迎收藏)

$(document).ready(function() {
//catch the right-click context menu
$(document).bind("contextmenu",function(e) { 
//warning prompt - optional
alert("No right-clicking!");
//delete the default context menu
return false;
});
});

$(document).ready(function() {
//find the current font size
var originalFontSize = $('html').css('font-size');
//Increase the text size
$(".increaseFont").click(function() {
var currentFontSize = $('html').css('font-size');
var currentFontSizeNumber = parseFloat(currentFontSize, 10);
var newFontSize = currentFontSizeNumber*1.2;
$('html').css('font-size', newFontSize);
return false;
});
//Decrease the Text Size
$(".decreaseFont").click(function() {
var currentFontSize = $('html').css('font-size');
var currentFontSizeNum = parseFloat(currentFontSize, 10);
var newFontSize = currentFontSizeNum*0.8;
$('html').css('font-size', newFontSize);
return false;
});
// Reset Font Size
$(".resetFont").click(function(){
$('html').css('font-size', originalFontSize);
});
});

$(document).ready(function() {
//select all anchor tags that have http in the href
//and apply the target=_blank
$("a[href^='http']").attr('target','_blank');
});

$(document).ready(function() {
$("a.cssSwap").click(function() { 
//swap the link rel attribute with the value in the rel 
$('link[rel=stylesheet]').attr('href' , $(this).attr('rel')); 
}); 
});

$(document).ready(function() {
//when the id="top" link is clicked
$('#top').click(function() {
//scoll the page back to the top
$(document).scrollTo(0,500);
}
});

$().mousemove(function(e){
//display the x and y axis values inside the P element
$('p').html("X Axis : "   e.pageX   " | Y Axis "   e.pageY);
});

$(document).ready(function() {
$().mousemove(function(e)
{
$('# MouseCoordinates ').html("X Axis Position = "   e.pageX   " and Y Axis Position = "   e.pageY);
});
});

jQuery.preloadImagesInWebPage = function() 
{
for(var ctr = 0; ctr<arguments.length; ctr  )
{
jQuery("<img alt="">").attr("src", arguments[ctr]);
}
}
To use the above method, you can use the following piece of code:
$.preloadImages("image1.gif", "image2.gif", "image3.gif");
To check whether an image has been loaded, you can use the following piece of code:
$('#imageObject').attr('src', 'image1.gif').load(function() {
alert('The image has been loaded…');
}); 

$.each( myArray, function( i, item ) {
var newListItem = "<li>"   item   "</li>";
$( "#ballers" ).append( newListItem );
}); 

var frag = document.createDocumentFragment();
$.each( myArray, function( i, item ) {
var newListItem = document.createElement( "li" );
var itemText = document.createTextNode( item );
newListItem.appendChild( itemText );
frag.appendChild( newListItem );
});
$( "#ballers" )[ ].appendChild( frag ); 

var myHtml = "";
$.each( myArray, function( i, item ) {
myHtml  = "<li>"   item   "</li>";
});
$( "#ballers" ).html( myHtml ); 

var myLength = myArray.length;
for ( var i = ; i < myLength; i   ) {
// do stuff
} 

var $table = $( "#myTable" );
var $parent = $table.parent();
$table.detach();
// ... add lots and lots of rows to table
$parent.append( $table ); 

// Bad: This runs three functions before it
// realizes there's nothing in the selection
$( "#nosuchthing" ).slideUp();
// Better:
var $mySelection = $( "#nosuchthing" );
if ( $mySelection.length ) {
$mySelection.slideUp();
}
// Best: Add a doOnce plugin.
jQuery.fn.doOnce = function( func ) {
this.length && func.apply( this );
return this;
}
$( "li.cartitems" ).doOnce(function() {

// make it ajax! \o/

}); 

// Fast:
$( "#container div.robotarm" );
// Super-fast:
$( "#container" ).find( "div.robotarm" ); 

// Unoptimized:
$( "div.data .gonzalez" );
// Optimized:
$( ".data td.gonzalez" ); 

$( ".data table.attendees td.gonzalez" );
// Better: Drop the middle if possible.
$( ".data td.gonzalez" ); 

$( ".buttons > *" ); // Extremely expensive.
$( ".buttons" ).children(); // Much better.
$( ".category :radio" ); // Implied universal selection.
$( ".category *:radio" ); // Same thing, explicit now.
$( ".category input:radio" ); // Much better. 

// Fine for up to elements, slow after that:
$( "a.swedberg" ).css( "color", "#ad" );
// Much faster:
$( "<style type=\"text/css\">a.swedberg { color: #ad }</style>")
.appendTo( "head" );