What : and? stands for?

syntax

[mariuz]

this.n_y = n_order
? o_parent.a_children[n_order - 1].n_y
: o_parent.n_y + this.getprop('block_top');

Can anyone explain why? and : are used for in above text?

[Sinner_G]

Welcome to WebmasterWorld, mariuz.

It is just a short form for an if/else.

In this case, it means if this.n_y is equal to n_order, then do what comes after the?, if not then do what comes after the :.

[dcrombie]

var somevar = (test condition)? "true value" : "false value";