Not allow Numbers

function NotAllowNumbers(object,e)//onkeyup

{

var Val=object.value;

var ValLen=object.value.length;

var LastVal=Val.substring(ValLen-1);

if(Numbers.indexOf(LastVal) > -1)

{

object.value=Val.substring(0,Val.indexOf(LastVal));

}

}

<input name="txtnotNum" type="text" id="txtOnlyHypen1"
onkeyup="javascript:NotAllowNumbers(this,event);"/>