title: How to use runat = "server" in input tag?
body: <p>I'm writing in asp.net. When I add <code>runat=&quot;server&quot;</code> property to my input tag, its value is null. When I remove <code>runat=&quot;server&quot;</code> it works correctly. Who knows the reason?</p>
  <p>I want change its property from code behind, that's why I wrote <code>runat=&quot;server&quot;</code>. However, the value is null.</p>
  <pre><code>protected void btnSaveChanges_Click(object sender, EventArgs e)
  {
      string current_id = Session[&quot;Current_user&quot;].ToString(); 
      string a = Request.Form[&quot;newusername&quot;]; 
      string b = Request.Form[&quot;newpassword&quot;]; 
      string c = Request.Form[&quot;rewpassword&quot;];
  }
  </code></pre>
  <p>Code for control:</p>
  <pre><code>&lt;input type=&quot;text&quot; name=&quot;newusername&quot; placeholder=&quot;Enter Username&quot; required=&quot;required&quot; runat=&quot;server&quot;/&gt;
  </code></pre>