Javascript Course

The function presented bellow can be used to shuffle /randomize array items in JavaScript.


Script code

// receive an array and return it with the items shuffled /randomized
function shuffle(ar){
 for(var j, x, i = ar.length; i; j = Math.floor(Math.random() * i), x = ar[--i], ar[i] = ar[j], ar[j] = x);
 return ar;
}
- Here is a simple example:
<h4>Example shuffle array in JavaScript</h4>
<p>Initial array: ar1 = ['a', 'b', 'c', 1, 2, 3];</p>

<button id='btntst'>Test Shuffle Array</button>
<script>
// receive an array and return it with the items shuffled /randomized
function shuffle(ar){
 for(var j, x, i = ar.length; i; j = Math.floor(Math.random() * i), x = ar[--i], ar[i] = ar[j], ar[j] = x);
 return ar;
}

var ar1 = ['a', 'b', 'c', 1, 2, 3];

//when click on the #btntst, show alert box with the items of ar1
document.getElementById('btntst').addEventListener('click', function(){
 ar1 = shuffle(ar1);
 alert(ar1);
});
</script>
Demo:
Initial array: ar1 = ['a', 'b', 'c', 1, 2, 3];

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 {
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  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
Shuffle / Randomize Array in JavaScript

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