验证用户控件输入值

Question

How to validate user control textbox value on Parent page? I have the following code but it couldn't find the control. I have checked IE View Source(HTML) and this control renders as

ctl00_Management_Initiation_txtTitle_txtInput

How to get the value using JQuery? Please let me know.

User Control

<telerik:RadTextBox id="txtInput" runat="server" TextMode="MultiLine" LabelCssClass=""></telerik:RadTextBox>&nbsp;
 <asp:image id="ImgRequired1" ImageUrl="../../images/requiredfield.gif" AlternateText="Required Field" Runat="server" Visible=false></asp:image><br /> 

.aspx page

<script type="text/javascript">
       $(document).ready(function () {
            $("#<%=btnSave.ClientID %>").click(function () {
                var valid = true;
                var msg = "Please fill form:\n";
                if($("input[id*=txtTitle]").val().length == 0{ 
                    msg += "Title is Required!\n";
                    valid = false;
                }
         });
});
</script>  


<uc1:ControlTextBox ID="txtTitle" runat="server" MaxLength="200" ></uc1:ControlTextBox>
   <asp:Button ID="btnSave" name="btnSave" runat="server" Text="Save"  />

Answer 1

if($("#<%= txtTitle.TextInputClientID %>").val().length == 0) { 

There is serious lack of closing brackets, both "}" and ")" in your javascript.

Add property to your user control:

public string TextInputClientID { get { return txtInput.ClientID; } }