Not understand how this checking-empty-form-value-code works (javascript)

Question

I came across this page and reading the example codes. I don't understand how the following line works in the the codes. How did it assign the value "\nlogin:" to the "error" variable when the form value is empty?

The line of code:

error+=f.login.value==''?'\nlogin':'';

The whole example code is under "2. Javascript is an enhancement, not a secure functionality".

Thanks for the help.

http://stackoverflow.com/questions/1771786/question-mark-in-javascript — JJJ, Jun 15 '13 at 17:58

score 2 · Accepted Answer · answered Jun 15 '13 at 17:56

2

It means:

if(f.login.value == '')
    error += '\nlogin'; 
else
    error += '';

The ?: syntax is called the ternary (or conditional) operator, and works like an inline if/else statement.

answered Jun 15 '13 at 17:56

bfavaretto

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Thanks for answering! I saw the ? in the codes but I could not comprehend that it was the ternary operator, because it was so compact! (And the single quotes confused me too) Now I see, thanks again! – Pete C. Jun 15 '13 at 18:03

Not understand how this checking-empty-form-value-code works (javascript)

1 Answers1