Why use “with” keyword in JavaScript? [duplicate]

Just don’t use it:
http://yuiblog.com/blog/2006/04/11/with-statement-considered-harmful/

JavaScript’s with statement was intended to provide a shorthand for writing recurring accesses to objects. So instead of writing

ooo.eee.oo.ah_ah.ting.tang.walla.walla.bing = true;
ooo.eee.oo.ah_ah.ting.tang.walla.walla.bang = true;

You can write

with (ooo.eee.oo.ah_ah.ting.tang.walla.walla) {
    bing = true;
    bang = true;
}

That looks a lot nicer. Except for one thing. There is no way that you can tell by looking at the code which bing and bang will get modifed. Will ooo.eee.oo.ah_ah.ting.tang.walla.walla be modified? Or will the global variables bing and bang get clobbered? It is impossible to know for sure…

If you can’t read a program and be confident that you know what it is going to do, you can’t have confidence that it is going to work correctly. For this reason, the with statement should be avoided…