window.showModalDialog is not working

I have the followi开发者_开发百科ng code to showModalDialog popup:---

.aspx code is:-

function ShowPopup(path) {
     window.showModalDialog(path, '', 'dialogWidth:700px; dialogHeight:530px; Center:yes');
}

My aspx.cs code is:--

switch (e.CommandName.ToLower())
{
    case "sendenquiry":
        string path = string.Format("/BusinessBazaarAspx/PopUps/Enquiry.aspx?c={0}", id);
        ScriptManager.RegisterClientScriptBlock(gvLatestCompanies, GetType(), "mykey2",
                                                string.Format("ShowPopup('{0}')", path), true);
         break;

But my Modal Popup is not visible...

Help me to get rid of this problem.

Thankx