Javascript – SCRIPT1004: Expected & # 39; & # 39 ;; Error in the browser

I'm using this script to hide the Edit button from the SharePoint Ribbon on the Ascx page of my custom Web Part and get it when the page loads:

            Function hideEdit ()
{

var edit = document.getElementById ("Ribbon.ListForm.Manage, EditItem-Large");

edit.style.display = "none";
alert ("I am an alarm box!");

}

_spBodyOnLoadFunctionNames.push ("hideEdit");

and I get two annoying mistakes:

1) SCRIPT1004: Expected ";"

2) SCRIPT5007: Property style of undefined or null can not be retrieved
reference

I have checked 100 times, no semicolon is missing. Is there any indication of what happens here?