JS_常用代码片段

 

1。查找元素位置

var getPagePos = function( el ){ var top = 0, left = 0, D = document; if( el.getBoundingClientRect ){ top = el.getBoundingClientRect().top + Math.max(D.documentElement.scrollTop, D.body.scrollTop); left = el.getBoundingClientRect().left + Math.max(D.documentElement.scrollLeft, D.body.scrollLeft); } else { top = el.offsetTop, left = el.offsetLeft; parentNode = el.offsetParent; if( parentNode != el ){ while ( parentNode ) { top += parentNode.offsetTop; left += parentNode.offsetLeft; parentNode = parentNode.offsetParent; } } } return { x: left , y: top }; } 

 

2。得到字节长度

// 得到字节长度 String.prototype.bytes = function() { return this.replace(/[^/x00-/xff]/g,"--").length; } 

 

3。延迟调用

Function.prototype.defer = function(delay, args){ var $pointer = this; if(!(args instanceof Array)) args = [args]; window.setTimeout(function(){ return $pointer.apply(this, args); }, delay); } 

 

4。获得浏览器屏幕窗口的大小

//获得浏览器屏幕窗口的大小 window.clientRect = function() { var w = (window.innerWidth) ? window.innerWidth : (document.documentElement && document.documentElement.clientWidth) ? document.documentElement.clientWidth : document.body.offsetWidth; var h = (window.innerHeight) ? window.innerHeight : (document.documentElement && document.documentElement.clientHeight) ? document.documentElement.clientHeight : document.body.offsetHeight; return {width:w,height:h}; } 

 

5。返回参数及参数表

//$pack函数当参数个数为1的时侯返回该参数，否则返回一个参数表 var $pack = function(){ if(arguments.length == 1) return arguments[0]; else return Array.apply(null, arguments); } 

 

6。简单浏览器判断

//判断是否是IE浏览器 function $isIE() { return /msie/i.test(navigator.userAgent); } //判断是否是Firefox浏览器 function $isFF() { return /firefox/i.test(navigator.userAgent); } //判断是否是IE7.0浏览器 function $isIE7() { return /msie 7/i.test(navigator.userAgent); }