Javascript Course


The array_map(), and array_search() functions are generally known and used in PHP. These functions are useful when working with arrays. JavaScript has similar functions, but with other syntax.

array.map()

The array.map(callback) method returns an array containing all the elements of array after applying the callback function to each one.
- Example:
var arr = [1, 4, 9, 16];

//creates an array with the values from arr, doubled
const arr2 = arr.map((v, i)=>v*2);

console.log(arr2); //[2, 8, 18, 32]

array.indexOf()

The JavaScript array.indexOf(value) method is equivalent to the php array_search(value, array) function, it searches the array for a given value and returns the corresponding index if successful, or -1 if none is found.
- Example:
let arr =['ab', 'cd', 90];
var ixv = arr.indexOf('cd');
if(ixv !=-1) document.write('<p>arr contains the value: cd, with index: '+ixv+'</p>');

Daily Test with Code Example

HTML
CSS
JavaScript
PHP-MySQL
Which tag renders as emphasized text, displaying the text oblique?
<strong> <pre> <em>
<p>Web development courses: <em>CoursesWeb.net</em></p>
Which CSS property defines the space between the element border and its content?
margin padding position
h3 {
  padding: 2px 0.2em;
}
Click on the method which returns the first element that matches a specified group of selectors.
getElementsByName() querySelector() querySelectorAll()
// gets first Div with class="cls", and shows its content
var elm = document.querySelector("div.cls");
alert(elm.innerHTML);
Indicate the PHP variable that contains data from a form sent with method="post".
$_SESSION $_GET $_POST
if(isset($_POST["field"])) {
  echo $_POST["field"];
}
array_map and array_search in JavaScript

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