解决 removeChild 的问题

var UIEntity = this;
var lblQty=UIEntity.lblCalcItemQty;
    var cmbTxt=UIEntity.cmbRedemOption[UIEntity.cmbRedemOption.selectedIndex].value;
var qunTxt=UIEntity.txtRedemQuantity.value;
var result=0;  
if(document.getElementById("lbl2")!=null)
{
document.getElementById("frm").removeNode(document.getElementById("lbl2"));
}
var frm=document.createElement("form");
frm.setAttribute("id","frm"); 
    var label2=document.createElement("label"); 
label2.setAttribute("id","lbl2"); 
frm.appendChild(label2);
lblQty.parentNode.insertBefore(frm,lblQty);
if (qunTxt == "" || isNaN(qunTxt))
{
        label2.innerText =result;
        return ;
}
result = cmbTxt*qunTxt;
label2.innerText=result;