[removed] || instead of IF statement - is this legal and cross browser valid?

Question

It seems that:

if (typeof a == \'undefined\') {
    a = 0;
}

and

(typeof a != \'undefined\') || (a = 0)

h

Answer 1

Stylistically, setting default values like a || a=default is a common idiom on entry into a function, because javascript doesn't enforce the number of arguments.

Readability will be compromised if this construct is used in other circumstances, where you really mean if/else.

Performance used to vary between the different styles, but in a quick test today if/else and logical operators were the same speed, but ternary operation was slower.