So what can you do with this trick?
You can edit content of any website including facebook,myspace,twitter etc.
How to perform this trick?
Open any website of your choice (like facebook) in browser (internet explorer,google chrome,firefox) and clear the address bar of the browser.
And thats it.Now you can edit anything that is written on the page.
How this trick actually work?
document.designMode=’on’ tells the browser to turn the designmode on
void 0 tells the browser not to show any error