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 HTML5 tag is indicated to be used as container for menu with navigation links in Web site?
<section> <nav> <article>
<nav><ul>
 <li><a href="http://coursesweb.net/css/" title="CSS Course">CSS Course</a></li>
 <li><a href="http://www.marplo.net/jocuri/" title="Flash Games">Flash Games</a></li>
</ul></nav>
Which CSS property shifts an item horizontally to the left or right of where it was?
text-align clear float
.some_class {
  width: 30%;
  float: left;
}
Click on the Math object method which returns x, rounded downwards to the nearest integer.
Math.ceil(x) Math.abs(x) Math.floor(x)
var num = 12.34567;
num = Math.floor(num);
alert(num);       // 12
Indicate the PHP function which returns the number of characters in string.
mb_strlen() count() stristr()
$str = "string with utf-8 chars åèö";
$nrchr = mb_strlen($str);
echo $nrchr;        // 30
array_map and array_search in JavaScript

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