<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <script> function boom() { document.setUserData('key', {}, null); // Depending on the pref bidi.direction, one of these will hit the page scrollbar. window.cpRight = document.caretPositionFromPoint(window.innerWidth - 1, 0); window.cpLeft = document.caretPositionFromPoint(0, 0); } </script> </head> <body onload="boom();"> <div style="height: 50000px;"></div> </body> </html>