js下用层来实现select的title提示属性

<script> 
             function opts(selectObj){ 
                         var optDivs=document.createElement("div"); 
                         var objTable=document.createElement("table"); 
                         var objTbody=document.createElement("tbody"); 
                         optDivs.style.zIndex = "100"; 
                         objTable.style.zIndex = "100"; 
                         objTable.width=selectObj.style.width;     
                         objTable.border = "0"; 
                         objTable.cellPadding = "0"; 
                         objTable.cellSpacing = "0"; 
                         objTable.style.paddingLeft = "2";     
                         objTable.style.fontFamily = "Verdana, Arial, Helvetica, sans-serif";                          var e = selectObj; 
                         var absTop = e.offsetTop; 
                         var absLeft = e.offsetLeft; 
                         var absWidth = e.offsetWidth; 
                         var absHeight = e.offsetHeight; 
                         while(e = e.offsetParent){ 
                         absTop += (e.offsetTop+0.3); 
                         absLeft += e.offsetLeft; 
                         } 
                         with (objTable.style){ 
                         position = "absolute"; 
                         top = (absTop + absHeight) + "px"; 
                         left = (absLeft+1) + "px"; 
                         border = "1px solid black"; 
                         tableLayout="fixed"; 
                         wordBreak="break-all"; 
                         } 
                         var options = selectObj.options; 
                         var val=selectObj.value; 
                            if (options.length > 0){ 
                                 for (var i = 0; i < options.length; i++){ 
                                     var newOptDiv = document.createElement("td"); 
                                     var objRow=document.createElement("tr"); 
                             newOptDiv.name=options[i].value; 
                             newOptDiv.innerText=options[i].innerText; 
                             newOptDiv.title=options[i].title; 
                             newOptDiv.onmouseout = function() {this.className='smouseOut';val=selectObj.value}; 
                             newOptDiv.onmouseover = function() {this.className='smouseOver';val=this.name;}; 
                             newOptDiv.className="smouseOut"; 
                             newOptDiv.style.width=40; 
                             newOptDiv.style.cursor="default"; 
                             newOptDiv.style.fontSize = "11px"; 
                             newOptDiv.style.fontFamily = "Verdana, Arial, Helvetica, sans-serif"; 
                             objRow.appendChild(newOptDiv); 
                             objTbody.appendChild(objRow); 
                             } 
                            } 
                     
                            objTbody.appendChild(objRow); 
                            objTable.appendChild(objTbody); 
                            optDivs.appendChild(objTable); 
                            document.body.appendChild(optDivs); 
                             var IfrRef = document.createElement("div"); 
                            IfrRef.style.position="absolute"; 
                            IfrRef.style.width = objTable.offsetWidth; 
                            IfrRef.style.height = objTable.offsetHeight; 
                            IfrRef.style.top = objTable.style.top; 
                            IfrRef.style.left = objTable.style.left; 
                            IfrRef.style.backgroundColor = document.bgColor; 
                            document.body.appendChild(IfrRef); 
                            objTable.focus(); 
                            objTable.onblur=function() {choose(selectObj,val,optDivs,IfrRef)}; 
         } 
         function choose(objselect,val,delobj,delobj2){ 
             objselect.value=val; 
             document.body.removeChild(delobj); 
             document.body.removeChild(delobj2); 
         } 
         </script> 
         
         <STYLE> 
                    .smouseOut { 
                            background: document.bgColor; 
                            color: #000000; 
                    } 
                    .smouseOver { 
                            background: rgb(0,128,128); 
                            color: #FFFFFF; 
                            cursor: pointer; 
                    } 
            </style> 
         
         <select id='selId'    style='width:50px' class='black' onclick="opts(this);"> 
                <option value='1' title="One....">111</option> 
                <option value='2' title="Two....">222</option> 
            </select>