jquery - How to use Media Queries in JavaScript - Stack Overflow

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I know little to nothing about JavaScript so I'm not even sure if my question makes sense. My point however is how to apply the same principle of media queries to change particular values on a script depending on the width of the screen.

In the following example, I'm using a scroll spy active menu with a negative scrolling of -100px for Header pensation. This offset is necessary because the header has a fixed position.

I need the offset value to change to 0px if window is smaller then 900px width, because at that point, Header position bees relative.

$(document).ready(function () {
$(window).scroll(function () {

    var y = $(this).scrollTop();

    $('.link').each(function (event) {
        if (y >= $($(this).attr('href')).offset().top - 100) {
            $('.link').not(this).removeClass('active');
            $(this).addClass('active');
        }
    });

});

});

$(function () {
$('a[href*=#]:not([href=#])').click(function () {
    if (location.pathname.replace(/^\//, '') == this.pathname.replace(/^\//, '') && location.hostname == this.hostname) {
        var target = $(this.hash);
        target = target.length ? target : $('[name=' + this.hash.slice(1) + ']');
        if (target.length) {
            $('html,body').animate({
                scrollTop: (target.offset().top - 100)
            }, 850);
            return false;
        }
    }
});

});

I know little to nothing about JavaScript so I'm not even sure if my question makes sense. My point however is how to apply the same principle of media queries to change particular values on a script depending on the width of the screen.

In the following example, I'm using a scroll spy active menu with a negative scrolling of -100px for Header pensation. This offset is necessary because the header has a fixed position.

I need the offset value to change to 0px if window is smaller then 900px width, because at that point, Header position bees relative.

$(document).ready(function () {
$(window).scroll(function () {

    var y = $(this).scrollTop();

    $('.link').each(function (event) {
        if (y >= $($(this).attr('href')).offset().top - 100) {
            $('.link').not(this).removeClass('active');
            $(this).addClass('active');
        }
    });

});

});

$(function () {
$('a[href*=#]:not([href=#])').click(function () {
    if (location.pathname.replace(/^\//, '') == this.pathname.replace(/^\//, '') && location.hostname == this.hostname) {
        var target = $(this.hash);
        target = target.length ? target : $('[name=' + this.hash.slice(1) + ']');
        if (target.length) {
            $('html,body').animate({
                scrollTop: (target.offset().top - 100)
            }, 850);
            return false;
        }
    }
});

});

• javascript
• jquery
• css
• scroll
• media-queries

Share Improve this question Follow asked Jan 23, 2015 at 14:14 David MartinsDavid Martins 2,05666 gold badges2626 silver badges3434 bronze badges 3

• $(window).on('resize',function() { if ($(window).width < 900) ... }) – Blazemonger Commented Jan 23, 2015 at 14:16
• 5 Why not use a CSS media query for this? I assume that the header is set to fixed via CSS at that resolution anyway? – Rory McCrossan Commented Jan 23, 2015 at 14:16
• @Blazemonger Thank you for your quick reply. I've tried your suggestion but I'm afraid I'm not doing it right. Would you be so kind as showing an example in context with the code I provided? Thanks a lot. – David Martins Commented Jan 23, 2015 at 14:39

Add a ment  | 

4 Answers 4

Sorted by: Reset to default 5

You actually do have something similar to Media Queries in JS:

if (matchMedia("(min-width: 900px)").matches) {
  // the viewport is at least 900 pixels wide
}

You can define .resolution-check class in css when to be visible:

@media only screen and (max-width: 900px) {
  .resolution-check {
    display: block;
  }
}

and then simply check in JS if that element is visible:

if ($('.resolution-check').is(':visible')) {

  // do stuff here

}

This way you can control media queries in one place, in CSS

function checkMatchMedia(pQuery) {
    if (!window.matchMedia) {return false;}
    if (window.matchMedia(pQuery).matches) {return true;}
    return false;
}

var vIsOK = checkMatchMedia("(min-width: 500px)");
if (vIsOK) {
    console.log('window width is at least 500px');
} else {
    if (window.matchMedia) {
        console.log('window width is less then 500px');
    } else {
        console.log('Please include Polyfill.');
    }
}

There is only a small problem with this, that is that older IE do not supports this.

This fixed with adding a libraries named polyfill .

How to use Media Queries in JavaScript and replace div or image or text Proto Theme Logo Change on mobile

jQuery(function($){ 
      if (window.matchMedia("(max-width: 500px)").matches) {
    $( ".vc_responsive .logo > a > img " ).replaceWith( "<img class='img-responsive standard-logo' src='your URL' alt='Xtreme'>" );
        }
        });

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