title: Do a database query on Textbox onblur event
body: <p>I am using asp.net 3.5 with C#. I need to do a database lookup when a user enters ProductID in txtProductID. I guess doing javascript is out of the question since this will have to be server side call. 
  I wrote this code in the page_load event of the webpage:</p>
  
  <pre><code>        protected void Page_Load(object sender, EventArgs e)
      {
          txtProductID.Attributes.Add("onblur", "LookupProduct()");
      }
  
          protected void LookupProduct()
      {
          //Lookup Product information on onBlur event;
      }
  </code></pre>
  
  <p>I get an error message: Microsoft JScript runtime error: Object expected
  How can I resolve this ?</p>