Textbox value in Javascript

The following Asp.Net program shows how to get asp.Net TextBox value by using JavaScript.

Asp.Net Code

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

The value property sets or returns the value of the value attribute of a text field. It contains the default value OR the value a user types in.

Full Source:

 
<html xmlns="http://www.w3.org/1999/xhtml">
  <head runat="server">
    <script type="text/javascript">
      function getValue() {
      var getVal = document.getElementById('<%= txt_id.ClientID %>').value;
      alert(getVal);
      }
    </script>
  </head>
  <body>
    <form id="form1" runat="server">
      <asp:TextBox ID="txt_id" runat="server" ></asp:TextBox>
      <br />
      <br />
      <input type="button" value="Get in Js" onclick="getValue()" />
      <br />
    </form>
  </body>
</html>

Setting Asp.Net Textbox value using Javascript

In order to set the value of textbox, we need to use:

 
document.getElementById(“txt_id”).value = inputValue;

Getting Asp.Net Label value using Javascript

Lets say you have a asp.net label like below

 
<asp:Label ID="lbl_id" runat="server" Text="Test Label"/>

then you can get the value of the above label using javascript using the below code

 
var getVal = document.getElementById("<%=lbl_id.ClientID %>").innerHTML;

Next : AutoEventWireup attribute in ASP.NET