js function to adjust select position_javascript skills

// Sorting: Move upward
Function up ()
... {
var sel = document.GetelementByid ("Selectcheck"); // Get selection
var nindex = sel.selectIndex;/ /The index of the select item that needs to be operated
var nLen = sel.length; //The total number of select items
if ((nLen if (nIndex ...{
alert("Please select a selected button to move!");
return;
} }
var sValue=sel.options[ nIndex].value;
var sHTML=sel.options[nIndex].innerHTML;
sel.options[nIndex].value=sel.options[nIndex-1].value;
sel.options[ nIndex].innerHTML=sel.options[nIndex-1].innerHTML; > sel.selectedIndex=nIndex-1; );
var nIndex = sel.selectedIndex;
var nLen = sel.length;
if ((nLen if ( nIndex ...{ 
  alert("Please select a selected button to move! ");
return; }
var sValue=sel.options[nIndex].value;
var sHTML=sel.options[nIndex].innerHTML; sel.options[nIndex ].value=sel.options[nIndex 1].value; 
 sel.options[nIndex].innerHTML=sel.options[nIndex 1].innerHTML; 
 sel.options[nIndex 1].value=sValue ; sel.options[nIndex 1].innerHTML=sHTML; sel.selectedIndex=nIndex 1;
}
//Move to the top
function UpFirst()
. . .{
var sel=document.getElementById("selectCheck");
var nIndex = sel.selectedIndex;
var nLen = sel.options.length;
if ((nLen

if(nIndex ...{
alert("Please select a selected button to move!");   
          return; 
      }
      var tempValue = document.getElementById("tempValue");//用于临时存放option的值
      tempValue.value = "";
      for(var k=0;k      ...{
         tempValue.value  =  sel.options[k].value ";";
      }
      var arrValue = tempValue.value.split(';');
      var   sValue=sel.options[nIndex].value;   
      var   sHTML=sel.options[nIndex].innerHTML;   
      sel.options[0].value = sValue;
      sel.options[0].innerHTML = sHTML;

     for(var j=1;j     ...{
       sel.options[j].value = arrValue[j-1];
       sel.options[j].innerHTML = arrValue[j-1];
     }
      sel.selectedIndex = 0;
   }
   //移动到最后
   function DownLast()
   ...{
      var   sel=document.getElementById("selectCheck"); 
      var   nIndex   =   sel.selectedIndex;  
      var   nLen = sel.options.length;
      if   ((nLen
      if(nIndex      ...{
          alert("请选择一个要移动的已选按钮！");   
          return; 
      }
      var tempValue = document.getElementById("tempValue");//用于临时存放option的值
      tempValue.value = "";
      for(var k=nIndex 1;k      ...{
         tempValue.value  =  sel.options[k].text ";";
      }
      var arrValue = tempValue.value.split(';');
      var   sValue=sel.options[nIndex].value;   
      var   sHTML=sel.options[nIndex].innerHTML;   

    
     for(var j=nIndex;j     ...{
       sel.options[j].value = arrValue[j-nIndex ];
       sel.options[j].innerHTML = arrValue[j-nIndex];
     }

      sel.options[nLen-1].value = sValue;
      sel.options[nLen-1].innerHTML = sHTML;
      sel.selectedIndex = nLen-1;
   }