JavaScript Array map () method
Examples
Returns an array of elements in the array is the square root of the original array:
var numbers = [4, 9, 16, 25];
function myFunction () {
x = document.getElementById ( "demo")
x.innerHTML = numbers.map (Math.sqrt);
}
function myFunction () {
x = document.getElementById ( "demo")
x.innerHTML = numbers.map (Math.sqrt);
}
The output is:
2,3,4,5
try it"
Definition and Usage
map () method returns a new array, the array of elements in the array element to its original value after the function call processing.
map () method in accordance with the order of elements in the original array processing elements.
Note: map () does not detect an empty array.
Note: map () does not change the original array.
Browser Support
Figures in the table represent the first browser to support the method version number.
| method | |||||
|---|---|---|---|---|---|
| map () | Yes | 9 | 1.5 | Yes | Yes |
grammar
array.map(function(currentValue,index,arr), thisValue)
Parameter Description
| parameter | description | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| function (currentValue, index, arr) | have to. Function, each element of the array will perform this function function parameters:
| ||||||||
| thisValue | Optional. As the callback object use, passed to the function, it is used as "this" value. If you omit thisValue, "this" value "undefined" |
technical details
| return value: | It returns a new array, the array of elements in the array element to its original value after the function call processing. |
|---|---|
| JavaScript version: | 1.6 |
More examples
Examples
Value input box specified for each element in the array multiplied, and returns a new array:
var numbers = [65, 44, 12, 4];
function multiplyArrayElement (num) {
return num * document.getElementById ( "multiplyWith" ) .value;
}
function myFunction () {
document.getElementById ( "demo") .innerHTML = numbers.map (multiplyArrayElement);
}
function multiplyArrayElement (num) {
return num * document.getElementById ( "multiplyWith" ) .value;
}
function myFunction () {
document.getElementById ( "demo") .innerHTML = numbers.map (multiplyArrayElement);
}
try it"