JS getStyle获取最终样式函数代码

#flower {
width:100px;
font-size:12px;
float:left;
opacity:0.5;
filter:alpha(opacity=50);
}

String.prototype.capitalize=function(){
return this.charAt(0).toUpperCase() + this.substring(1).toLowerCase();
}
Array.prototype.contains=function(A){
return (this.indexOf(A) >= 0);
}
String.prototype.camelize=function(){
return this.replace(/\-(\w)/ig,
function(B, A) {
return A.toUpperCase();
});
}
var css={
getStyle:function(elem,styles){
var value,
elem=document.getElementById(elem);
if(styles == "float"){
document.defaultView ? styles = 'float' /*cssFloat*/ : styles='styleFloat';
}
value=elem.style[styles] || elem.style[styles.camelize()];
if(!value){
if (document.defaultView && document.defaultView.getComputedStyle) {
var _css=document.defaultView.getComputedStyle(elem, null);
value= _css ? _css.getPropertyValue(styles) : null;
}else{
if (elem.currentStyle){
value = elem.currentStyle[styles.camelize()];
}
}
}
if(value=="auto" && ["width","height"].contains(styles) && elem.style.display!="none"){
value=elem["offset"+styles.capitalize()]+"px";
}
if(styles == "opacity"){
try {
value = elem.filters['DXImageTransform.Microsoft.Alpha'].opacity;
value =value/100;
}catch(e) {
try {
value = elem.filters('alpha').opacity;
} catch(err){}
}
}
return value=="auto" ? null :value;
}
}
css.getStyle("flower","width"); //100px;
css.getStyle("flower","font-size");//12px;
css.getStyle("flower","float");//left
css.getStyle("flower","opacity");//0.5

if(value=="auto" && ["width","height"].contains(styles) && elem.style.display!="none"){
value=elem["offset"+styles.capitalize()]+"px";
}

try {
value = elem.filters['DXImageTransform.Microsoft.Alpha'].opacity;
value =value/100;
}catch(e) {
try {
value = elem.filters('alpha').opacity;
} catch(err){}
}