Shielding the right mouse button, F1 Help and common shortcut keys

With the shortcut key/*** the right mouse button, F1 Help and the common shortcut key * author:huangyuyuan* Date:2004-09-10*/function shield () {function Document.oncontextmenu ( ) {Event.returnvalue=false;} right mouse button function Window.onhelp () {return false}//mask F1 help function Document.onkeydown () {if (Window.event.altKey) & & ((window.event.keycode==37) | |//Shielding ALT + Direction key ← (window.event.keycode==39))//shielding ALT + Direction key →{alert ("You are not allowed to use ALT + Direction key forward or after Back page! "); Event.returnvalue=false; }/* Note: This is not really shielding ALT + direction key, because ALT + arrow pop-up warning box, hold down the ALT key, with the mouse point off the warning box, this shielding method is ineffective. In the future, if there is a real master to screen the Alt key method, please inform. */if ((event.keycode==8) | |//SHIELDING BACKSPACE Delete key (event.keycode==116) | |/Mask F5 Refresh key (Event.ctrlkey && event.keycode==82)) {/ /ctrl + R event.keycode=0; Event.returnvalue=false; } if (event.keycode==122) {event.keycode=0;event.returnvalue=false;}//Mask F11 if (Event.ctrlkey && event.keycode==78) Event.returnvalue=false; Shielding CTRL + N if (event.shiftkey && event.keycode==121) Event.returnvalue=false; Shielding SHIFT+F10 if (window.event.srcElement.tagName = = "A" &&Amp Window.event.shiftKey) Window.event.returnValue = false; Screen shift plus left mouse button new page if ((Window.event.altKey) && (window.event.keycode==115))//Shield Alt+f4 { Window.showmodelessdialog ("About:blank", "" "," dialogwidth:1px;dialogheight:1px "); return false; } }}