What's mean that syntax in JS?

Question

I found in web script, allowed unwind div.

function toggle(sDivId) {
    var oDiv = document.getElementById(sDivId);
    oDiv.style.display = (oDiv.style.display == "none") ? "block" : "none";
}

Whats mean that line: (oDiv.style.display == "none") ? "block" : "none";

[Conditional (ternary) operator](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Operators/Conditional_Operator) — Turnip, Dec 20 '16 at 15:36

score -1 · Accepted Answer · answered Dec 20 '16 at 15:36

-1

it's a ternary operator, or "inline if" as some call it

oDiv.style.display = (oDiv.style.display == "none") ? "block" : "none";

is the same as:

if(oDiv.style.display == "none") {
    oDiv.style.display = "block";
} else {
    oDiv.style.display = "none";
}

answered Dec 20 '16 at 15:36

Stu

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so simple, thanks :) – Dec 20 '16 at 15:44

score -1 · Answer 2 · answered Dec 20 '16 at 15:36

This is ternary operator. More information here

condition ? expr1 : expr2

If condition is true, the operator returns the value of expr1; otherwise, it returns the value of expr2.

Basically, a short hand of If else statement.

if(oDiv.style.display == "none")) {
 oDiv.style.display = "block" } 
else {
oDiv.style.display = "none";}

score -1 · Answer 3 · answered Dec 20 '16 at 15:36

This is a ternary operator, it is basically saying the following...

Is display = "none"? If so, set "block", if not set "none"

Simply put...

Condition?true:false;

function toggle(sDivId) {
            var oDiv = document.getElementById(sDivId);
            oDiv.style.display = (oDiv.style.display == "none") ? "block" : "none";
            // Is this element display set to none? ? yes  ? no
           }

What's mean that syntax in JS?

3 Answers3