title: How to change the label text in javascript function?
body: <p>i want to validate login page using java script function.
  i take one label button for displaying message and two text box for username and password and one button for "Login" . </p>
  
  <p>when user click on "Login" button without enterning username and password then message will be display in label control. So how to check textbox value in javascript function and how to change the value in lblmessage. I call this function in Ok button . I set this function on Button OnClientClick event but this does not work.</p>