<script type="text/javascript">
$(document).ready(function () {
$("#error").hide();
$("#txtStuAge").keyup(function () {
var $val = $("#txtStuAge").val();
var code;
for (var i = 0; i < $val.length; i++) {
//charAt()获取指定位置字符串,charCodeAt()返回该字符串的编码
//0的ASCII是48,9的ASCII是57
var code = $val.charAt(i).charCodeAt(0);
if (code < 48 || code > 57) {
$("#error").show();
break;
}
else {
$("#error").hide();
}
}
});
});
</script>
前台: <asp:TextBox ID="txtStuAge" runat="server"></asp:TextBox><span id="error">请输入数字!</span>