JS常用的兼容方法

var getStyle = function( obj , attr ){
return obj.currentStyle?obj.currentStyle[attr]:getComputedStyle(obj)[attr];
};

var getClass = function(cName,obj){
obj = obj||document;
if (obj.getElementsByClassName)
{
return obj.getElementsByClassName(cName);
}
else
{
var arr = [];
var tagName = obj.getElementsByTagName('*');
var reg = new RegExp("\\b"+cName+"\\b");
for (var i = 0; i < tagName.length; i++) {
if (reg.test(tagName[i].class))
{
arr.push(tagName[i]);
}
}
return arr;
}

}