Do not enter a debug point when I try to make the OnValueChanged event in a HiddenField?

I want to make certain that the value of my textbox that is hidden is certain actions in my codebehind and apparently it should work with the OnValueChanged event but when I try to debug that part of my code it just does not work stops and it's as if he did not enter.

Hidden Code

<input type="file" id="fuFile"  />
                <asp:HiddenField ID="HFFile" runat="server" 
OnValueChanged="HFFile_OnValueChanged"  />
                <asp:HyperLink runat="server" Style="cursor:pointer">Ver 
Anexos</asp:HyperLink>

Event code OnValueChanged

protected void HFFile_OnValueChanged(object sender, EventArgs e)
    {
        string prueba = HFFile.Value;
    }