.Net Interview Questions, Resources, Tips & Tricks.

In case of HTML control in your web page:

< input type="text" id="txtName" />
you can access this value as document.getElementById('txtName').value;
or $get('txtName')

Suppose you have a Web server control like TextBox in your Web page:

< asp:TextBox id="Test" Text="Sample" runat="server">

You can access this value in a couple ways using JavaScript:

document.forms[0]['Test'].value;

(or)

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

ClientID - server control identifier generated by ASP.NET
You should use ClientId for accessing Server control always especially when we have Master Pages or the control is inside of other server controls like Panel, Gridview etc. As in all these cases server generates ClientId dynamically and which will vary time to time or in some browser instances.