JavaScript for DownListBox Accept NoDuplicates

function CheckNoDuplicate()
{
var iCount = 0;

EmployeeName = document.form1.txt1.value.replace(/^\s+|\s+$/g,"");
for(var i=1; i < document.form1.ddl1.options.length ; i++)
{
//alert(document.form1.ddl1.options[i].text);

if(document.form1.ddl1.options[i].text == EmployeeName)
{
iCount++;
if(iCount == 1)
{
alert("\tEntered 'EmployeeName Title' already exists...!" );
document.form1.txt1.focus();
return false;
}
}

}
}