Using Javascript to check form input while using ASP.NET

Question

My school is running a project to build a website that containts register and login . Of course , the level of the instructors in my country is low , and we are required to use Javascript to check the inputs in the form , instead of using ASP.NET to do it .

So , let's get to the question :

I'm having few inputs , like this :

<asp:TextBox id="usname" runat="server" MaxLength="20" value="שם משתמש" TextMode="SingleLine" CssClass="usernameInput" onfocus="this.value=''"></asp:TextBox>
            <asp:TextBox ID="email" runat="server" MaxLength="40" value="אימייל" TextMode="SingleLine" CssClass="emailInput" onfocus="this.value=''"></asp:TextBox>
            <asp:TextBox ID="password" runat="server" MaxLength="20" value="סיסמה" TextMode="Password" CssClass="passwordInput" onfocus="this.value=''"></asp:TextBox>
            <asp:TextBox ID="passwordRepeat" runat="server" MaxLength="20" value="אימות סיסמה" TextMode="Password" CssClass="passwordRepeatPassword" onfocus="this.value=''"></asp:TextBox>

While trying to identify the field with it's id , Javascript won't recognize it . What can I do in order to keep this Textboxes , and check the input with Javascript ?

Thanks in advance , Iliya

Have you looked at ASP.NET validation controls? msdn.microsoft.com/en-us/library/bwd43d0x%28v=vs.100%29.aspx The can so some degree of javascript validation for you. — russau
– russau, Commented May 10, 2013 at 16:41

SLaks · Accepted Answer · 2013-05-10 16:38:13Z

4

ASP.Net generates its own unique IDs for server-side controls.

You can prevent this by setting the ClientIDMode property to Static.

answered May 10, 2013 at 16:38

SLaks

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Santosh Panda · Accepted Answer · 2013-05-11 18:55:01Z

1

You can try with the following option:

document.getElementById('<%=ControlId.ClientID %>');

Example:

function CheckInput()
{
    var userName = document.getElementById('<%=usname.ClientID %>');
    var mail = document.getElementById('<%=email.ClientID %>');
    var pwd = document.getElementById('<%=password.ClientID %>');
    var pwdRepeat = document.getElementById('<%=passwordRepeat.ClientID %>');

    // Your validation logic

    if (userName == "XYZ" && mail == "[email protected]" && pwd == "1234" &&
        pwdRepeat == "1234")
    {
        return true;
    }

    else
    {
        return false;
    }
}

And you can call this from your button click as follows:

<asp:Button ID="Button1" runat="server" Text="Button" 
 OnClientClick="javascript:return CheckInput();" />

The above javascript will either return true or false. If it returns True then the button will postback to server.

edited May 11, 2013 at 18:55

answered May 10, 2013 at 17:03

Santosh Panda

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1 Comment

Iliya Vaitzman Over a year ago

Thanks to all of you ! How can I make the site use the Javascript function when pressing on the submit , and if it returned true , to do the submit to the Code Behind ?

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