ASP.NET Textbox AutoPostBack Not Firing
<p>After searching I've found a number of suggestions, but none of them are fixing the issue.  </p>

<pre><code>&lt;asp:TextBox runat="server" ID="uid" AutoPostBack="True" Text=""&gt;&lt;/asp:TextBox&gt;
</code></pre>

<p>In the properties window, EnableViewState = True for the TextBox (<a href="http://forums.asp.net/t/1198167.aspx" rel="nofollow">Suggested here</a>). I am typing a new value into the TextBox and then hitting the Tab key.  Nothing happens nor does the break point at if(IsPostBack...) break.</p>

<p>Code Behind:</p>

<pre><code>protected void Page_Load(object sender, EventArgs e)
    {
        if(IsPostBack &amp;&amp; uid.Text != "" &amp;&amp; pw.Text == "")
        {
            Do stuff
        }
    }
</code></pre>

<p>UPDATE: Other TextBox setups I've tried:</p>

<pre><code>&lt;asp:TextBox runat="server" ID="uid" Text="" AutoPostBack="True" OnTextChanged="UidTextChanged"&gt;&lt;/asp:TextBox&gt;

protected void UidTextChanged(object sender, EventArgs e)
    {
        ClientScript.RegisterStartupScript(GetType(), "alert", "alert('it works');", true);
    }
</code></pre>

<p>And</p>

<pre><code> &lt;asp:TextBox runat="server" ID="uid" AutoPostBack="True" Text="" onblur="__doPostBack('','');" OnTextChanged="UidTextChanged"&gt;&lt;/asp:TextBox&gt;
</code></pre>

<p>And</p>

<pre><code> &lt;asp:TextBox runat="server" ID="uid" AutoPostBack="True" Text="" onblur="__doPostBack('','');"&gt;&lt;/asp:TextBox&gt;
</code></pre>

<p>Whenever AutoPostBack is set to true, I receive the following error in the browser console:</p>

<pre><code>"Uncaught TypeError: Property 'submit' of object #&lt;HTMLFormElement&gt; is not a function
__doPostBack
(anonymous function)"
</code></pre>

<p>When I have the onblur property set, I receive the exact same error except instead of anonymous function it says onblur.</p>
