JavaScript获取css属性的兼容写法

 //注意：IE8及以下不支持querySelector也不支持getElementsByClassNamevar imgbox=document.querySelector("#box");  

        function getStyle(elem,attr){                    if(window.getComputedStyle){       //W3C                        return window.getComputedStyle(elem,"")[attr];                     }else if(elem.currentStyle){     //IE                        return elem.currentStyle[attr];                    }else{                        return null;                    }                }

        alert(getStyle(imgbox,"height")) //[]里面是要加引号的，所以height加引号传进去