Question

When I run this simple greasemonkey script

alert("hello");
alert(document.location);
document.write("hello");
alert("hello");

Only the first two statements work, the third and fourth statement do nothing.

What could be wrong here?

Answer 1

It seems that document.write() only works intermittently from Greasemonkey — maybe due to the sandbox.

I haven’t found a foolproof recipe for duplicating the issue yet.

However, the DOM-based approach always seems to work. Use this code:

//--- Erase everything from the page's body:
var b           = document.body;
var p           = b.parentNode;
p.removeChild (b);


//--- Add our new text or HTML.
var newB        = document.createElement ("BODY");
newB.innerHTML  = "Hello";
p.appendChild (newB);

PS: I updated my other answer as well.