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Conditional Operator


The conditional operator is the only JavaScript operator that takes three operands. This operator is frequently used as a shortcut for the if statement.

Implemented in: JavaScript 1.0
ECMA Version: ECMA-262


condition ? expr1 : expr2


An expression that evaluates to true or false.
expr1, expr2
Expressions with values of any type.


If condition is true, the operator returns the value of expr1; otherwise, it returns the value of expr2. For example, to display a different message based on the value of the isMember variable, you could use this statement:

document.write ("The fee is " + (isMember ? "$2.00" : "$10.00"))

You can also assign variables depending on a ternary result:

var elvisLives = Math.PI > 4 ? "Yep" : "Nope";

Multiple ternary evaluations are also possible (note: the conditional operator is right associative):

var hadRelations = false,
  isSure = false,
  presidentQuote = hadRelations ? "Had relations" : isSure ? "Did not have relations" : "I admit";
console.log( presidentQuote ); // Prints "I admit" in the console

You can also use ternary evaluations in free space in order to do different operations:

var bStop = false, nAge = 16;

nAge > 18 ? location.assign("continue.html") : bStop = true;

You can also do more than one single operation per case, separating them with a comma:

var bStop = false, nAge = 23;

nAge > 18 ? (
    alert("Ok, you can go."),
) : (
    bStop = true,
    alert("Sorry, you are much too young!")

You can also do more than one operation during the assignation of a value. In this case, the last comma-separated value of the parenthesis will be the value to be assigned.

var nAge = 16;

var sURL = nAge > 18 ? (
    alert("Ok, you can go."), // alert returns "undefined", but it will be ignored because isn't the last comma-separated value of the parenthesis
    "continue.html" // the value to be assigned if nAge > 18
) : (
    alert("You are much too young!"),
    alert("Sorry :-("),
    // etc. etc.
    "stop.html" // the value to be assigned if !(nAge > 18)

location.assign(sURL); // "stop.html"

Document Tags and Contributors

Contributors to this page: Sevenspade
Last updated by: Sevenspade,