jQuery实用技巧必备（上）

本文实例总结了经典且实用的jQuery代码开发技巧。分享给大家供大家参考。具体如下：

1. 禁止右键点击

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

2. 隐藏搜索文本框文字
Hide when clicked in the search field, the value.(example can be found below in the comment fields)

$(document).ready(function() {
$("input.text1").val("Enter your search text here");
 textFill($('input.text1'));
});
 
 function textFill(input){ //input focus text function
 var originalvalue = input.val();
 input.focus( function(){
  if( $.trim(input.val()) == originalvalue ){ input.val(''); }
 });
 input.blur( function(){
  if( $.trim(input.val()) == '' ){ input.val(originalvalue); }
 });
}

3. 在新窗口中打开链接
XHTML 1.0 Strict doesn't allow this attribute in the code, so use this to keep the code valid.

$(document).ready(function() {
 //Example 1: Every link will open in a new window
 $('a[href^="http://"]').attr("target", "_blank");
 
 //Example 2: Links with the rel="external" attribute will only open in a new window
 $('a[@rel$='external']').click(function(){
 this.target = "_blank";
 });
});
// how to use
<a href="http://www.jb51.com" rel=external>open link</a>

4. 检测浏览器
注: 在版本jQuery 1.4中，$.support 替换掉了$.browser 变量

$(document).ready(function() {
// Target Firefox 2 and above
if ($.browser.mozilla && $.browser.version >= "1.8" ){
 // do something
}

// Target Safari
if( $.browser.safari ){
 // do something
}

// Target Chrome
if( $.browser.chrome){
 // do something
}

// Target Camino
if( $.browser.camino){
 // do something
}

// Target Opera
if( $.browser.opera){
 // do something
}

// Target IE6 and below
if ($.browser.msie && $.browser.version <= 6 ){
 // do something
}

// Target anything above IE6
if ($.browser.msie && $.browser.version > 6){
 // do something
}
});

5. 预加载图片
This piece of code will prevent the loading of all images, which can be useful if you have a site with lots of images.

$(document).ready(function() {
jQuery.preloadImages = function()
{
 for(var i = 0; i<ARGUMENTS.LENGTH; jQuery(?<img { i++)>").attr("src", arguments[i]);
 }
}
// how to use
$.preloadImages("image1.jpg");
});

6. 页面样式切换

$(document).ready(function() {
 $("a.Styleswitcher").click(function() {
 //swicth the LINK REL attribute with the value in A REL attribute
 $('link[rel=stylesheet]').attr('href' , $(this).attr('rel'));
 });
// how to use
// place this in your header
<LINK rel=stylesheet type=text/css href="default.css">
// the links
<A class=Styleswitcher href="#" rel=default.css>Default Theme</A>
<A class=Styleswitcher href="#" rel=red.css>Red Theme</A>
<A class=Styleswitcher href="#" rel=blue.css>Blue Theme</A>
});

7. 列高度相同
如果使用了两个CSS列，使用此种方式可以是两列的高度相同。

$(document).ready(function() {
function equalHeight(group) {
 tallest = 0;
 group.each(function() {
 thisHeight = $(this).height();
 if(thisHeight > tallest) {
  tallest = thisHeight;
 }
 });
 group.height(tallest);
}
// how to use
$(document).ready(function() {
 equalHeight($(".left"));
 equalHeight($(".right"));
});
});

8. 动态控制页面字体大小
用户可以改变页面字体大小

$(document).ready(function() {
 // Reset the font size(back to default)
 var originalFontSize = $('html').css('font-size');
 $(".resetFont").click(function(){
 $('html').css('font-size', originalFontSize);
 });
 // Increase the font size(bigger font0
 $(".increaseFont").click(function(){
 var currentFontSize = $('html').css('font-size');
 var currentFontSizeNum = parseFloat(currentFontSize, 10);
 var newFontSize = currentFontSizeNum*1.2;
 $('html').css('font-size', newFontSize);
 return false;
 });
 // Decrease the font size(smaller font)
 $(".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;
 });
});

9. 返回页面顶部功能
For a smooth(animated) ride back to the top(or any location).

$(document).ready(function() {
$('a[href*=#]').click(function() {
 if (location.pathname.replace(/^\//,'') == this.pathname.replace(/^\//,'')
 && location.hostname == this.hostname) {
 var $target = $(this.hash);
 $target = $target.length && $target
 || $('[name=' + this.hash.slice(1) +']');
 if ($target.length) {
 var targetOffset = $target.offset().top;
 $('html,body')
 .animate({scrollTop: targetOffset}, 900);
 return false;
 }
 }
 });
// how to use
// place this where you want to scroll to
<A name=top></A>
// the link
<A href="#top">go to top</A>
});

10. 获得鼠标指针ＸＹ值
Want to know where your mouse cursor is?

$(document).ready(function() {
 $().mousemove(function(e){
 //display the x and y axis values inside the div with the id XY
 $('#XY').html("X Axis : " + e.pageX + " | Y Axis " + e.pageY);
 });
// how to use
<DIV id=XY></DIV>

});

11.返回顶部按钮
你可以利用 animate 和 scrollTop 来实现返回顶部的动画，而不需要使用其他插件。

// Back to top
$('a.top').click(function () {
 $(document.body).animate({scrollTop: 0}, 800);
 return false;
});
<!-- Create an anchor tag -->
<a class="top" href="#">Back to top</a>

改变scrollTop 的值可以调整返回距离顶部的距离，而 animate 的第二个参数是执行返回动作需要的时间(单位：毫秒)。

今天为大家先介绍一部分jQuery技巧，后续文章会继续更新，希望大家持续关注。