js method to implement Select drop-down box with input function_javascript skills

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<script><br> var Select = {<br> del : function(obj,e){<br> if((e.keyCode||e.which||e.charCode) == 8){<br> var opt = obj.options[0];<br> opt.text = opt.value = opt.value.substring(0, opt.value.length>0?opt.value.length-1:0);<br> }<br> },<br> write : function(obj,e){<br> if((e.keyCode||e.which||e.charCode) == 8)return ;<br> var opt = obj.options[0];<br> opt.selected = "selected";<br> opt.text = opt.value = String.fromCharCode(e.charCode||e.which||e.keyCode);<br> }<br> }<br> function test(){<br> alert(document.getElementById("select").value);<br> }<br> </script>