Remove an Item from a dropdownlist

I have Asp.net 4.0 application.In this Application, am having a dropdownlist and a button.When the page loads, the dropdwlist is  loading with 5 items. When I Click on the button, need to delete  selected item from the dropdowlist permantely.for this, wrote a javascript method for and it is have the code like
varx = document.getElementById("DropDownList1");
            x.remove(2);
After excute the code , the same item is existing ...