title: how to get variable value in javascript
body: <p>I have script in <code>aspx</code> page so I want that variable value in another JavaScript file.</p>
  
  <pre><code>function ValidateStartDate() 
  {
     var txtDate = document.getElementById('&lt;%=txtDateFilterActv.ClientID  %&gt;');
     var lastdate = txtDate.value;
  }
  </code></pre>
  
  <p>After click on save button I want '<code>lastdate</code>' variable value in another JavaScript file. How can I access it?</p>