JavaScript验证用户输入的是字符或数字及ASCII Chart应用

<script type = "text/javascript"> 
function isNumeric(keyCode) 
{ 
return ((keyCode >= 48 && keyCode <= 57) || keyCode == 8) 
} 
</script> 
<script type = "text/javascript"> 
function isAlpha(keyCode) 
{ 
return ((keyCode >= 65 && keyCode <= 90) || keyCode == 8) 
} 
</script> 
<script type = "text/javascript"> 
function isAlphaOrNumeric(keyCode) 
{ 
return ((keyCode >= 48 && keyCode <= 57) || (keyCode >= 65 && keyCode <= 90) || keyCode == 8) 
} 
</script> 
 
例子，用户只能输入字符和数字，并使用onpaste事件，不能粘贴。 
 代码如下:

<asp:TextBox ID="TextBox1" runat="server" onkeydown = "return isAlphaOrNumeric(event.keyCode);" onpaste = "return false;"></asp:TextBox>