Question

83

rated 0 times [ 89] [ 6] / answers: 1 / hits: 99849 / 15 Years ago, tue, november 24, 2009, 12:00:00

I can’t seem to wrap my head around the first part of this code ( += ) in combination with the ternary operator.

h.className += h.className ? ' error' : 'error'

The way I think this code works is as follows:

h.className = h.className + h.className ? ' error' : 'error'

But that isn't correct, because that gives a error in my console.

How should I interpret this code correctly?

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3 Years ago

answered 15 Years ago mira · Accepted Answer

Use:

h.className = h.className + (h.className ? ' error' : 'error')

You want the operator to work for h.className. Better be specific about it.

Of course, no harm should come from h.className += ' error', but that's another matter.

Also, note that + has precedence over the ternary operator: JavaScript Operator Precedence