simple javascript question

Question

Possible Duplicate:
javascript ? : notation

what does the "?" operator mean?

So this ternary operator walks into a a bar... – Gleno Sep 20 '10 at 00:22 — Gleno, Sep 20 '10 at 00:22

score 3 · Answer 1 · edited Sep 20 '10 at 00:25

3

it means an inline if

condition ? true_statement : false_statement

e.g

if(condition){
alert("true");
}else{
alert("false");
}

is the same as condition ? alert("true"): alert("false");

edited Sep 20 '10 at 00:25

Femaref

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answered Sep 20 '10 at 00:19

bevacqua

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For reference, the conditional operator's true and false parts should be values, not actions. I'd recommend `alert(condition ? "true" : "false")` instead -- though in this particular case, `alert(condition.toString())` may work as well. Either way, if you have to decide between two actions, use `if`/`else`; if you're deciding between two values, use `?:` – cHao Sep 20 '10 at 00:28
1

I was just showing that it can work just as a regular if, though you are right, it can be used like return (condition ? "ok" : "nope"); – bevacqua Sep 20 '10 at 00:32

score 1 · Answer 2 · answered Sep 20 '10 at 00:19

1

It, along with : comprises the ternary operator and is a shortcut for returning one of two values (the second and third sub-expressions), based on the result of the condition (the first sub-expression).

Wikipedia gives a good description: http://en.wikipedia.org/wiki/%3F:#Javascript

It's used like this:

var result = (condition ? value_for_true : value_for_false);

Example:

var result = (1 > 0 ? "It is greater" : "It is less");

The above example stores "It is greater" in the variable result.

On its own, ? does nothing except cause a syntax error when used without :.

answered Sep 20 '10 at 00:19

Chris Laplante

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thanks, looked on google but it took the "?" to mean question. – Dirty Bird Design Sep 20 '10 at 00:22
Sure. It's a common feature in many languages by the way: http://en.wikipedia.org/wiki/%3F. Not just JavaScript. – Chris Laplante Sep 20 '10 at 00:23

score 1 · Answer 3 · answered Sep 20 '10 at 00:19

1

It's part of the ternary operator.

// This simple if
if (25 > 23) {
    alert("yes");
} else {
    alert("no");
}

// Is the same as
alert(25 > 23 ? "yes" : "no");

answered Sep 20 '10 at 00:19

rebelliard

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score 1 · Answer 4 · edited May 23 '17 at 11:55

1

You probably mean the ?:, or ternary, operator. Since this has been covered multiple times before, I'll refer you to this thread for a full explanation.

edited May 23 '17 at 11:55

Community

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answered Sep 20 '10 at 00:21

deceze

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It's actually the [JS conditional operator](https://developer.mozilla.org/en/JavaScript/Reference/Operators/Special_Operators/Conditional_Operator), which is the only ternary operator in JS. – Peter Ajtai Sep 20 '10 at 00:37
Ya know, people are gonna get rather confused if there ever ends up being another ternary operator. They won't know what to call the existing one anymore. – cHao Sep 20 '10 at 18:25

simple javascript question

4 Answers4