js动态创建DOM元素 示例

        function sAlert(str){
        var msgw,msgh,bordercolor;
        msgw=400;//提示窗口的宽度
        msgh=100;//提示窗口的高度
        titleheight=25 //提示窗口标题高度
        bordercolor="#c51100";//提示窗口的边框颜色
        titlecolor="#c51100";//提示窗口的标题颜色
        
        var sWidth,sHeight;
        sWidth=screen.width;
        sHeight=screen.height;

        var bgObj=document.createElement("div");
        bgObj.setAttribute('id','bgDiv');
        bgObj.style.position="absolute";
        bgObj.style.top="0";
        bgObj.style.background="#cccccc";
        bgObj.style.filter="progid:DXImageTransform.Microsoft.Alpha(style=3,opacity=25,finishOpacity=75";
        bgObj.style.opacity="0.6";
        bgObj.style.left="0";
        bgObj.style.width=sWidth + "px";
        bgObj.style.height=sHeight + "px";
        bgObj.style.zIndex = "10000";
        document.body.appendChild(bgObj);
        
        var msgObj=document.createElement("div")
        msgObj.setAttribute("id","msgDiv");
        msgObj.setAttribute("align","center");
        msgObj.style.background="white";
        msgObj.style.border="1px solid " + bordercolor;
        msgObj.style.position = "absolute";
        msgObj.style.left = "50%";
        msgObj.style.top = "50%";
        msgObj.style.font="12px/1.6em Verdana, Geneva, Arial, Helvetica, sans-serif";
        msgObj.style.marginLeft = "-225px" ;
        msgObj.style.marginTop = -75+document.documentElement.scrollTop+"px";
        msgObj.style.width = msgw + "px";
        msgObj.style.height =msgh + "px";
        msgObj.style.textAlign = "center";
        msgObj.style.lineHeight ="25px";
        msgObj.style.zIndex = "10001";
        msgObj.style.position = "absolute";

       var box=document.getElementById(str);
       var title=document.createElement("h4");
       title.setAttribute("id","msgTitle");
       title.setAttribute("align","right");
       title.style.margin="0";
       title.style.padding="3px";
       title.style.background=bordercolor;
       title.style.filter="progid:DXImageTransform.Microsoft.Alpha(startX=20, startY=20, finishX=100, finishY=100,style=1,opacity=75,finishOpacity=100);";
       title.style.opacity="0.75";
       title.style.border="1px solid " + bordercolor;
       title.style.height="18px";
       title.style.font="12px Verdana, Geneva, Arial, Helvetica, sans-serif";
       title.style.color="white";
       title.style.cursor="pointer";
       title.onmousedown=function(){startDrag(this,'msgDiv')};
       title.onmouseup=function(){stopDrag(this,'msgDiv')};
       title.onmousemove=function(){drag('msgDiv')};
       var closer=document.createElement("div");
       closer.onclick=function(){
                   CloseReturn();
                   document.body.appendChild(box);
                box.style.display = "none";
                document.body.removeChild(bgObj);
                document.getElementById("msgDiv").removeChild(title);
                document.body.removeChild(msgObj);
            };
       closer.innerHTML="确定";
       document.body.appendChild(msgObj);
       document.getElementById("msgDiv").appendChild(title);
       document.getElementById("msgTitle").appendChild(closer);
       box.style.display="inline";
       document.getElementById("msgDiv").appendChild(box);
       ShowReturn();
        }