10 个实用的jQuery 代码片段详解编程语言

(function($) { 
  var cache = []; 
  // Arguments are image paths relative to the current page. 
  $.preLoadImages = function() { 
    var args_len = arguments.length; 
    for (var i = args_len; i--;) { 
      var cacheImage = document.createElement('img'); 
      cacheImage.src = arguments[i]; 
      cache.push(cacheImage); 
    } 
  } 
 
jQuery.preLoadImages("image1.gif", "/path/to/image2.png");

2. 在新窗口打开链接 (target=”blank”)   

$('a[@rel$='external']').click(function(){ 
     this.target = "_blank"; 
}); 
 
/* 
   Usage: 
   <a href="http://www.catswhocode.com" rel="external">catswhocode.com</a> 
*/

3. 当支持 JavaScript 时为 body 增加 class   

/* 该代码只有1行，但是最简单的用来检测浏览器是否支持 JavaScript 的方法，如果支持 JavaScript 就在 body 元素增加一个 hasJS 的 class */ 
$('body').addClass('hasJS');

4. 平滑滚动页面到某个锚点   

$(document).ready(function() { 
	$("a.topLink").click(function() { 
		$("html, body").animate({ 
			scrollTop: $($(this).attr("href")).offset().top + "px" 
		}, { 
			duration: 500, 
			easing: "swing" 
		}); 
		return false; 
	}); 
});

5. 鼠标滑动时的渐入和渐出  

$(document).ready(function(){ 
    $(".thumbs img").fadeTo("slow", 0.6); // This sets the opacity of the thumbs to fade down to 60% when the page loads 
 
    $(".thumbs img").hover(function(){ 
        $(this).fadeTo("slow", 1.0); // This should set the opacity to 100% on hover 
    },function(){ 
        $(this).fadeTo("slow", 0.6); // This should set the opacity back to 60% on mouseout 
    }); 
});

6. 制作等高的列 

var max_height = 0; 
$("div.col").each(function(){ 
    if ($(this).height() > max_height) { max_height = $(this).height(); } 
}); 
$("div.col").height(max_height);

7. 在一些老的浏览器上启用 HTML5 的支持 

(function(){ 
    if([email protected]_on!@*/0) 
        return; 
    var e = "abbr,article,aside,audio,bb,canvas,datagrid,datalist,details,dialog,eventsource,figure,footer,header,hgroup,mark,menu,meter,nav,output,progress,section,time,video".split(','),i=e.length;while(i--){document.createElement(e[i])} 
})() 
 
//然后在head中引入该js 
<!--[if lt IE 9]> 
<script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script> 
<![endif]-->

8. 测试浏览器是否支持某些 CSS3 属性

var supports = (function() { 
   var div = document.createElement('div'), 
      vendors = 'Khtml Ms O Moz Webkit'.split(' '), 
      len = vendors.length; 
 
   return function(prop) { 
      if ( prop in div.style ) return true; 
 
      prop = prop.replace(/^[a-z]/, function(val) { 
         return val.toUpperCase(); 
      }); 
 
      while(len--) { 
         if ( vendors[len] + prop in div.style ) { 
            // browser supports box-shadow. Do what you need. 
            // Or use a bang (!) to test if the browser doesn't. 
            return true; 
         } 
      } 
      return false; 
   }; 
})(); 
 
if ( supports('textShadow') ) { 
   document.documentElement.className += ' textShadow';

9. 获取 URL 中传递的参数

$.urlParam = function(name){ 
	var results = new RegExp('[//?&]' + name + '=([^&#]*)').exec(window.location.href); 
	if (!results) { return 0; } 
	return results[1] || 0; 
}

10. 禁用表单的回车键提交

$("#form").keypress(function(e) { 
  if (e.which == 13) { 
    return false; 
  } 
});