摘要:利用javascirpt 限制只能輸入數字 使用ASCII碼
------------------------------------------------ Input 控制項作法 ------------------------------------------------------
	<script language="JavaScript" type="text/javascript">
	    function CheckKey(key) {
	        if (key >= 48 && key <= 57)
	         { return true; }
	         else { return false; }
	    }
	 </script>
<input type="text" name="birthday" onkeypress="return CheckKey(event.keyCode)" />
------------------------------------------- Asp.net 利用 cs 程式碼去操控 -----------------------------------------------
	    protected void LoadScript()
	    {
	        StringBuilder oSB = new StringBuilder();
	        oSB.AppendFormat("document.getElementById('{0}').onkeydown = function()", txtGoPage.ClientID);
	        oSB.Append("{");
	        oSB.Append("if(event.keyCode>47 && event.keyCode<58 ){");
	        oSB.Append("return true;");
	        oSB.Append("}else{");
	        oSB.Append("return false;}");
	        oSB.Append("};");
	        if (this.Page.ClientScript.IsStartupScriptRegistered(this.GetType(), "jsPage") == false)
	        {
	            this.Page.ClientScript.RegisterStartupScript(this.GetType(), "jsPage", oSB.ToString(), true);
	        }
	    }