CustomValidator not showing error message from javascript

Question

I am practising client side validations with server side. I have written a code in client side to validate name and it is returing the value. But problem is that for incorrect values the error message is not displaying as soon as focus lost from the text box. My implementation is as:

Updated

 <script type="text/javascript">
    function validateText(osrc, args) {
        var textvalue = args;
        var pattern = /^[a-zA-Z.]{3,25}$/
        if (textvalue != null || textvalue != "") {
            if (pattern.test(textvalue)) {

                args.isValid = true;
            }
            else
                args.isValid = false;
        }
        else args.isValid = false;
        return;
    }
</script>

and aspx page contents are

<asp:TextBox runat="server" ID="txtFirstName" CssClass="form-control" />
            <asp:CustomValidator runat="server" Display="Dynamic" CssClass="text-danger"
                 ControlToValidate="txtFirstName" ToolTip="Incorrect Text" ErrorMessage="*"
                 EnableViewState="false" ValidateEmptyText="true" EnableClientScript="true"
                 Enabled="true" ClientValidationFunction="validateText"></asp:CustomValidator>//This validator is not showing the error message

What's wrong with it, help required.

Please change: "var textvalue = args" to "var textvalue = args.Value" — lucidgold
– lucidgold, Commented Jun 20, 2014 at 20:19

lucidgold · Accepted Answer · 2014-06-20 20:47:28Z

2

You must set the value of args.IsValid to TRUE or FALSE instead of just returning true/false. Also you need to use args.Value (notice V is uppercase) to set textvalue correctly. And you are only supposed to RETURN IF/WHEN the expression is valid:

JavaScript:

function validateText(osrc, args) {
    var textvalue = args.Value; //notice V is uppercase!
    var pattern = /^[a-zA-Z.]{3,25}$/
    if (textvalue != null || textvalue != "") {
        if (pattern.test(textvalue)) {
            args.IsValid = true;
            return; //notice we ONLY return when the expression IS valid
        }
        args.IsValid = false;
    }
    args.IsValid = false;
}

ASPX:

<div class="col-md-10">
    <asp:Label ID="Label1" runat="server" AssociatedControlID="txtFirstName" 
               CssClass="col-md-2 control-label">First Name</asp:Label>
    <asp:TextBox runat="server" ID="txtFirstName" CssClass="form-control" />
    <asp:CustomValidator ID="CustomValidator1" runat="server" 
                         Display="Dynamic" ControlToValidate="txtFirstName" 
                         ToolTip="Incorrect Text" ErrorMessage="*" 
                         EnableViewState="false" 
                         ValidateEmptyText="true" 
                         EnableClientScript="true" 
                         Enabled="true" 
                         ClientValidationFunction="validateText">
        Please input a valid First Name!
    </asp:CustomValidator>
    <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"  
                                ControlToValidate="txtFirstName"
                                CssClass="text-danger" 
                                ErrorMessage="First name is required" 
                                ToolTip="First name is required." 
                                EnableViewState="False" />
</div>

edited Jun 20, 2014 at 20:47

answered Jun 20, 2014 at 20:00

lucidgold

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4 Comments

Hassaan Over a year ago

i have done and debug the function is returning the value but the error is still not displaying?

lucidgold Over a year ago

Please update your code in your question so we know what you have so far

lucidgold Over a year ago

I have updated my code, there was an issue with the return statement. You are ONLY supposed to RETURN IF/WHEN the expression is VALID. Also I made some changes to the ASPX. You will now see "Please input a valid First Name!" error

Greg B Over a year ago

The comments about only returning when the field is valid are incorrect. The only thing that matters is that args.IsValid is correct when the function returns (naturally or via return;). See stackoverflow.com/questions/31095104

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