完全兼容的 鼠标滚轴缩放图片

code如下： 

 

/*!
 *Author:sohighthesky
 *blog:http://www.cnblogs.com/sohighthesky
 *date:2010-2-4
 */
var zooming=function(e){
    e=window.event ||e;
    var o=this,data=e.wheelDelta || -e.detail*40,zoom,size;
    if(!+'\v1'){//IE
        zoom = parseInt(o.style.zoom) || 100; 
        zoom += data / 12;
        if(zoom > zooming.min) 
            o.style.zoom = zoom + '%';
        e.returnValue=false;
    }else {
        size=o.getAttribute("_zoomsize").split(",");
        zoom=parseInt(o.getAttribute("_zoom")) ||100;
        zoom+=data/12;
        if(zoom>zooming.min){
            o.setAttribute("_zoom",zoom);
            o.style.width=size[0]*zoom/100+"px";
            o.style.height=size[1]*zoom/100+"px"
        }

        e.preventDefault();//阻止默认行为
    }
};
zooming.add=function(obj,min){//第一个参数指定可以缩放的图片，min指定最小缩放的大小 ,default to 50
    zooming.min=min || 50;
    obj.onmousewheel=zooming;
    if(/a/[-1]=='a')//if Firefox
        obj.addEventListener("DOMMouseScroll",zooming,false);
    if(-[1,]){//if not IE
        obj.setAttribute("_zoomsize",obj.offsetWidth+","+obj.offsetHeight);
    }
};

window.onload=function(){//放在onload中，否则非ie中会无法计算图片大小出错
    zooming.add(document.getElementById("testimg1"));
}