Javascript Course

The JavaScript code snippet presented in this page can be used to refresh the page if the window width is changed from a device size (mobile, or tablet, or desktop size) to other.
- For examples, if you have in your page some content with different settings for desktop, tablet, and mobile size; if the user resizes the window from full size to a lower window-width (or viceversa), the page is refreshed so to have the content according to current browser's width.

Script code

Add the code in the page you want to refresh it according to window width. Then, to test it, rezise the browser.

<h4>Resize the window</h4>

/* JS code to refresh the page if window is changed (from: ) */
function winSize() {
 // returns an object with height and width of the window
 var win_size = {};
 if (self.innerHeight) {
 win_size.height = self.innerHeight;
 win_size.width = self.innerWidth;
 } else if (document.documentElement && document.documentElement.clientHeight) {
 win_size.height = document.documentElement.clientHeight;
 win_size.width = document.documentElement.Width;
 } else if (document.body) {
 win_size.height = document.body.clientHeight;
 win_size.width = document.body.clientWidth;
 return win_size;
var win_size = winSize();

// set indice "m" for mobile (max. 400px), "t" for tablet (max. 700px), "d" for desktop, according to window size
var dev_i = (win_size.width <400) ? 'm' : ((win_size.width <700) ? 't' :'d');

// when Resize browser, check window-width; refresh if current device indice not initial device indice
window.addEventListener('resize', function(e){
 var win_size2 = winSize();
 var dev_i2 = (win_size2.width <400) ? 'm' : ((win_size2.width <700) ? 't' :'d');
 if(dev_i2 != dev_i) window.location.replace(window.location.href);
}, false);

The script refreshes the page according to these two sizes: 400px, and 700px. If you want to have one size that determines the refresh, modify the variables: var dev_i and var dev_i2.
For example:

var dev_i = (win_size.width <500) ? 'm' : 'd';
var dev_i2 = (win_size2.width <500) ? 'm' :'d';

Daily Test with Code Example

What attribute makes a radio button or checkbox input selected?
checked="checked" selected="selected" disabled="disabled"
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What CSS value scales the background image to the largest size contained within the element?
repeat-x contain linear-gradient
#id {
What operator is used to determine the rest of the division of two numbers?
% * /
var rest8_7 = 8 % 7;
Indicate the PHP function that rounds a number up to the next highest integer.
floor() ceil() abs()
$nr = ceil(3.5);
echo $nr;        // 4
Refresh page if window width changes from a device size to other

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