How can I modify the existing title to the document with Jquery as mouseover title change like that on facebook title link.
I'll extend on these other answers, this code should do it in entirety, just be sure to change the class in the selector, and the new Title Text.
(function(){
var oldtitle;
jQuery('a.yourlink').hover(
function () {
oldtitle = document.title;
document.title = 'Your New Title';
},
function () {
document.title = oldtitle;
}
);
})();
Here is a jsfiddle demo I made that changes the text of the object, rather than the window title: http://jsfiddle.net/MpZGf/1/