Question

I have a line of jQuery code that is causing an error as I placed two periods in front of the b class. I am wondering how does jQuery interpret the following line? If I had only one period in front of b instead of two, I assume that jQuery interpret it as: “if class b exists within class a which exists in the parent of this, alert prompt hi”.

if ( $(this).parent().find(".a ..b") ) {
  alert("hi");
});

Answer 1

.a ..b is an invalid selector and it will throw error:

Uncaught Error: Syntax error, unrecognized expression: .

.a .b is the correct selector.

So $(this).parent().find(".a .b") will first fetch the direct parent node of this, then it will search for a descendant element with the class="a" and then another descendant element within with the class="b", and if it finds it will alert hi.