用javascript来实现select标签的美化的代码(2)

/************************************
*    js模拟Select                    *

*    Author:Daviv                    *

*    Date:2007-4-28                    *

*    Blog:        *

*    Email:jxdawei#163.com            *
************************************/

var childCreate=false;

function Offset(e)
//取标签的绝对位置
{
    var t = e.offsetTop;
    var l = e.offsetLeft;
    var w = e.offsetWidth;
    var h = e.offsetHeight-2;

    while(e=e.offsetParent)
    {
        t+=e.offsetTop;
        l+=e.offsetLeft;
    }
    return {
        top : t,
        left : l,
        width : w,
        height : h
    }
}

function loadSelect(obj){

    //第一步：取得Select所在的位置
    var offset=Offset(obj);
    //第二步：将真的select隐藏
    obj.style.display="none";

    //第三步：虚拟一个div出来代替select
    var iDiv = document.createElement("div");
        iDiv.id="selectof" + obj.name;
        iDiv.style.position = "absolute";
        iDiv.style.width=offset.width + "px";
        iDiv.style.height=offset.height + "px";
        iDiv.style.top=offset.top + "px";
        iDiv.style.left=offset.left + "px";
        iDiv.style.background="url(icon_select.gif) no-repeat right 4px";
        iDiv.style.border="1px solid #3366ff";
        iDiv.style.fontSize="12px";
        iDiv.style.lineHeight=offset.height + "px";
        iDiv.style.textIndent="4px";
    document.body.appendChild(iDiv);

    //第四步：将select中默认的选项显示出来
    var tValue=obj.options[obj.selectedIndex].innerHTML;
    iDiv.innerHTML=tValue;

    //第五步：模拟鼠标点击
    iDiv.onmouseover=function(){//鼠标移到
        iDiv.style.background="url(icon_select_focus.gif) no-repeat right 4px";
    }
    iDiv.onmouseout=function(){//鼠标移走
        iDiv.style.background="url(icon_select.gif) no-repeat right 4px";
    }
    iDiv.onclick=function(){//鼠标点击
        if (document.getElementById("selectchild" + obj.name)){
        //判断是否创建过div
            if (childCreate){
                //判断当前的下拉是不是打开状态，如果是打开的就关闭掉。是关闭的就打开。
                document.getElementById("selectchild" + obj.name).style.display="none";
                childCreate=false;
            }else{
                document.getElementById("selectchild" + obj.name).style.display="";
                childCreate=true;
            }
        }else{
            //初始一个div放在上一个div下边，当options的替身。
            var cDiv = document.createElement("div");
            cDiv.id="selectchild" + obj.name;
            cDiv.style.position = "absolute";
            cDiv.style.width=offset.width + "px";
            cDiv.style.height=obj.options.length *20 + "px";
            cDiv.style.top=(offset.top+offset.height+2) + "px";
            cDiv.style.left=offset.left + "px";
            cDiv.style.background="#f7f7f7";
            cDiv.style.border="1px solid silver";

            var uUl = document.createElement("ul");
            uUl.id="uUlchild" + obj.name;
            uUl.style.listStyle="none";
            uUl.style.margin="0";
            uUl.style.padding="0";
            uUl.style.fontSize="12px";
            cDiv.appendChild(uUl);
            document.body.appendChild(cDiv);        
            childCreate=true;
            for (var i=0;i<obj.options.length;i++){
                //将原始的select标签中的options添加到li中
                var lLi=document.createElement("li");
                lLi.id=obj.options[i].value;
                lLi.style.textIndent="4px";
                lLi.style.height="20px";
                lLi.style.lineHeight="20px";
                lLi.innerHTML=obj.options[i].innerHTML;
                uUl.appendChild(lLi);
            }
            var liObj=document.getElementById("uUlchild" + obj.name).getElementsByTagName("li");
            for (var j=0;j<obj.options.length;j++){
                //为li标签添加鼠标事件
                liObj[j].onmouseover=function(){
                    this.style.background="gray";
                    this.style.color="white";
                }
                liObj[j].onmouseout=function(){
                    this.style.background="white";
                    this.style.color="black";
                }
                liObj[j].onclick=function(){
                    //做两件事情，一是将用户选择的保存到原始select标签中，要不做的再好看表单递交后也获取不到select的值了。
                    obj.options.length=0;
                    obj.options[0]=new Option(this.innerHTML,this.id);
                    //同时我们把下拉的关闭掉。
                    document.getElementById("selectchild" + obj.name).style.display="none";
                    childCreate=false;
                    iDiv.innerHTML=this.innerHTML;
                }
            }
        }
    }
}

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