javascript works on IE but doesnt on firefox and chrome
<p>This piece of javascript code works only on IE why and how can i make it work on firefox and chrome.
Thanks in advance.</p>

<p>Javascript</p>

<pre><code> function uploadFileChange() {
        if (document.getElementById('textbox1').value != document.getElementById("FileUpload1").value) {
            document.getElementById('textbox1').value = document.getElementById("FileUpload1").value;
        }
        return false;
    }
</code></pre>

<p>HTML/asp.net</p>

<pre><code>&lt;div class="fileinputs"&gt;
    &lt;!-- Upload file invisivel--&gt;
    &lt;asp:FileUpload ID="FileUpload1" ClientIDMode="Static" class="file" runat="server"
        onpropertychange="uploadFileChange();" /&gt;
    &lt;!-- button e textbox falsas para poder dar syles ao button--&gt;
    &lt;div class="fakefile"&gt;
        &lt;asp:TextBox ID="textbox1" CssClass="textbox" ClientIDMode="Static" runat="server"
            Width="31%" ReadOnly="true" /&gt;
        &lt;asp:Button ID="FileChooserButton1" CssClass="btnSubmit" runat="server" Text="Procurar..."
            ForeColor="White" /&gt;
        &lt;asp:Button ID="FileChooserButton2" CssClass="btnSubmit" Text="Apagar" ForeColor="White"
            OnClientClick="clear();" runat="server" /&gt;
    &lt;/div&gt;
&lt;/div&gt;
</code></pre>

<p>RESOLVED</p>
