No Alphabet JavaScript

  1. function noAlphabet(e) 
  2. {  
  3.            var regex = new RegExp("[0-9]");  
  4.            var key = e.keyCode || e.which;  
  5.            key = String.fromCharCode(key);  
  6.   
  7.            if (!regex.test(key)) 
  8.            {  
  9.                e.returnValue = false;  
  10.                if (e.preventDefault) 
  11.                {  
  12.                    e.preventDefault();  
  13.                }  
  14.            }  
  15. }  
  1. <asp:TextBox ID="qty" runat="server" CssClass="form-control" onkeypress="return noAlphabet(event)" MaxLength="3"></asp:TextBox>