代碼如下:
protected override void OnPreRender(EventArgs e)
{

base.OnPreRender(e);
RenderJS();
}

private void RenderJS()
{
if (!Page.ClientScript.IsClientScriptBlockRegistered(SCRIPT_ID))//如果還沒有注冊語句，則注冊
{
Page.ClientScript.RegisterClientScriptBlock(this.GetType(),SCRIPT_ID,SCRIPT_CONTENT);
}

}
private const string SCRIPT_ID = "5B7A061B93D546A7A2601D56A8738DB9";//自定義標識Guid
private const string SCRIPT_CONTENT = "<script type=/"text/javascript/">/nvar CB4949501DA_checkDouble = function (data) {/nvar key = event.keyCode;/nif ((key < 48 || key > 57) && key != 46 && key != 45) {/nreturn false;/n}/nelse {/nif (key == 46) {/nif (data.indexOf(/"./") != -1 || data.length == 0)/nreturn false;/n}/nelse if (key == 45) {/nif (data.indexOf(/"-/") != -1 || data.length != 0) {/nreturn false;/n}/n}/n}/nreturn true;/n}/nvar CB4949501DA_checkInt = function (data) {/nvar key = event.keyCode;/n/nif ((key < 48 || key > 57) && key != 45) {/nreturn false;/n}/nelse {/nif (key == 45) {/nif (data.indexOf(/"-/") != -1 || data.length != 0) {/nreturn false;/n}/n}/nelse {/nvar input = String.fromCharCode(key)/nvar intData = parseInt(data + input);/nif (intData > 2147483647 || intData < -2147483648) {/nreturn false;/n}/n}/nreturn true;/n}/nreturn true;/n}/nvar <span style="color:#ff0000;">CB4949501DA_checkLong </span>= function (data) {/nvar key = event.keyCode;/n/nif ((key < 48 || key > 57) && key != 45) {/nreturn false;/n}/nelse {/nif (key == 45) {/nif (data.indexOf(/"-/") != -1 || data.length != 0) {/nreturn false;/n}/n}/nelse {/nvar input = String.fromCharCode(key)/nvar longstrData = data + input/nif (longstrData.length > 19) {/nreturn false;/n}/n}/n}/nreturn true;/n}/n</script>/n";

再添加代碼去調用寫入的javascript函數：
代碼如下:
protected override void AddAttributesToRender(System.Web.UI.HtmlTextWriter writer)
{

base.AddAttributesToRender(writer);
writer.AddAttribute("onkeypress", "return <span style="color:#ff0000;">CB4949501DA_checkLong</span>(this.value);");}

另外，引用文件是這樣的。
代碼如下:
if (!Page.ClientScript.IsClientScriptIncludeRegistered("引用js文件1"))//如果還沒有引用，則引用
{
Page.ClientScript.RegisterClientScriptInclude("引用js文件1", "JS/MYJS.JS");
}

生成的頁面查看源代碼效果如下：
代碼如下:
<script src="JS/MYJS.JS" type="text/javascript"></script>
<script type="text/javascript">
var CB4949501DA_checkDouble = function (data) {
var key = event.keyCode;
if ((key < 48 || key > 57) && key != 46 && key != 45) {
return false;
}
else {
if (key == 46) {
if (data.indexOf(".") != -1 || data.length == 0)
return false;
}
else if (key == 45) {
if (data.indexOf("-") != -1 || data.length != 0) {
return false;
}
}
}
return true;