Script executes but code-behind not
<p>I have a button on my aspx page. With this button, I'll add a option element into a select element and add some data to a GridView displayed on the page. I want to put the option element first than executes my code-behind from  this button.</p>

<p>I have the button and the evaluated combobox:</p>

<pre><code>&lt;asp:DropDownList runat="server" ID="comboboxPeople" ... /&gt;
&lt;asp:DropDownList runat="server" ID="comboboxOutput" /&gt;
&lt;asp:Button runat="server" ID="buttonAdd" text="Add passanger" OnClick="buttonAdd_Click" OnClientClick="addOptionToSelectElement();" /&gt;
</code></pre>

<p>I have the script:</p>

<pre><code>function addOptionToSelectElement() {
    var cb = document.getElementById('&lt;%=comboboxPeople.ClientID %&gt;');
    var cbout = document.getElementById('&lt;%=comboboxOutput.ClientID %&gt;');
    var op = document.createElement("op");
    op.value = cb.options[cb.selectedIndex].value;
    op.text = cb.options[cb.selectedIndex].text;
    cbout.appendChild(op);
}
</code></pre>

<p>And my code-behind:</p>

<pre><code>protected void buttonAdd_Click(object sender, EventArgs e)
{
    DoSomething(...);
}
</code></pre>

<p>Here's my problem: If I attach the script function to my button, the code-behind doesn't work. If I don't use the script, my code-behind runs.</p>

<p>Any idea?
Thanks!!</p>
