What Is The Order Of Precedence For Boolean Operators In Js?

e.pageX = e.clientX + (html && html.scrollLeft || body && body.scrollLeft || 0) - (html.clientLeft || 0) how would this expression evaluate?

Solution 1:

You can find a precedence table for Javascript operators on MDN: https://developer.mozilla.org/en/JavaScript/Reference/Operators/Operator_Precedence. It is a great source for Javascript documentation in general.

Anyway, && has higher precedence than || so a && b || c || d is equivalent to (((a && b) || c) || d). This is similar to many other language with a C-inspired syntax.