OnClick event of button fires everytime on PageLoad
<p>I have a button below:</p>

<pre><code> &lt;asp:Button ID="btnApprove" runat="server" Text="Approve" CssClass="button" OnClick="btnApprove_Click" /&gt;
</code></pre>

<p>Event handler of this button on server side is :</p>

<pre><code> protected void btnApprove_Click(object sender, EventArgs e)
    {
        Page.ClientScript.RegisterStartupScript(Page.GetType(), "key", "alert('Button Approve Clicked')", true);      
    }
</code></pre>

<p>Just get alert on the button click from the server side.</p>

<p>My issue is that once I clicked on Approve button, now when I load or refresh my page again this <code>btnApprove_Click</code> event gets executed everytime.</p>

<p>I have many others button on the same form but none shows this strange kind of behaviour. I tried to change this button as HTML but still the same behaviour.</p>

<p>Can anyone please help me to get out of it. Thanks in advance.</p>