No-frills tab renamer. I'll give 5 stars if you fix the bug where pressing "cancel" on the popup renames the tab to "null". Should be easy to fix.
I read the source code and I suggest something like this:


var ttl = prompt("Enter new title");

/*Only renames tab if prompt returns a "truthy" value, aka not an empty string, null, undefined, etc.*/
if(ttl){
document.title = ttl;
}