how to call the c# function on mouse over

lblcolorname.Attributes.Add("onmouseover", "imgcalal()");
//adding attribute to label

public void imgcalal()
{
document.getElementById('you imagebuttonid').click();
//we are firing click event of image button
}

<asp:imagebutton id="imagebutton" onclick="btnsearch_Click" />
//html image button have already defined c# function onclick

protected void btnsearch_Click(object sender, EventArgs e)
   {

// this will be executed
}