Possilbe to change sticky top position when viewport changes?

[eSilverStrike]

I have 2 sticky items, the top navigation menu bar, and a module on the left side bar.

Everything works great expect when the top navigation menu bar gets changed to a slide out left menu for mobile devices with small viewports.

Is it possible to change the module to a new top position when the view port has changed? This way I am not left with a white space at the top.

Thanks for a great plugin.

[heathdutton]

There are a few ways to accomplish this.

For us, we use a css/sass workaround:

body:before {
  display: none !important;
  @include breakpoint(xs) {
    content: 'xs' !important;
  }
  @include breakpoint(sm) {
    content: 'sm' !important;
  }
  @include breakpoint(md) {
    content: 'md' !important;
  }
  @include breakpoint(lg) {
    content: 'lg' !important;
  }
}

Basically, we're exploiting the :before pseudo-element to ensure that our stylesheet breakpoints are always retrievable by javascript by effectively modifying the DOM, regardless of how those breakpoints may change in our sass. You can do this with standard CSS as well, of course.

Next in JS, we do something like:

$(window).resize(function () {
      var breakpoint = window
          .getComputedStyle( document.querySelector('body'), ':before' )
          .getPropertyValue( 'content' )
          .replace(/['"]+/g, '');
    // Do the thing based on the breakpoint.
});

[eSilverStrike]

Thanks for your solution. I will give this a try. I haven't used SASS yet so I will go about this using standard css.

[mhulse]

Another approach that works well with Bootstrap 3 breakpoints (you'd have to replicate the classes/breakpoints to work in a non-Bootstrap environment):

Put this anywhere in your document:

<span id="mq-detector">
    <span class="visible-xs" data-id="0"></span>
    <span class="visible-sm" data-id="1"></span>
    <span class="visible-md" data-id="2"></span>
    <span class="visible-lg" data-id="3"></span>
</span>

Then this JS:

$(function() {

    // https://stackoverflow.com/a/28373319/922323
    // https://github.com/garand/sticky/issues/211
    // https://github.com/JoshBarr/on-media-query

    var $sticky = $('.sticky');
    var options = {
        topSpacing: 10,
        responsiveWidth: true
    };

    $sticky.sticky(options);

    $('body').on('BREAKPOINT', function(event, size) {
        if (size <= 1) {
            $sticky.unstick();
        } else {
            $sticky.sticky(options);
        }
    });

});

//----------------------------------------------------------------------
// THIS SHOULD COME LAST!
//----------------------------------------------------------------------

$(function() {

    var mqDetector = $('#mq-detector');
    var mqSelectors = [
        mqDetector.find('.visible-xs'),
        mqDetector.find('.visible-sm'),
        mqDetector.find('.visible-md'),
        mqDetector.find('.visible-lg')
    ];

    var checkForResize = function() {
        for (var i = 0; i <= mqSelectors.length; i++) {
            if (mqSelectors[i].is(':visible')) {
                if (window.BREAKPOINT != i) {
                    window.BREAKPOINT = i;
                    console.log(mqSelectors[i].attr('class'));
                    $('body').trigger('BREAKPOINT', mqSelectors[i].data('id'));
                }
                break;
            }
        }
    };

    window.BREAKPOINT = undefined;

    $(window).on('resize', checkForResize);

    checkForResize();

});

Links:

• https://stackoverflow.com/a/28373319/922323
• Possilbe to change sticky top position when viewport changes? #211
• https://github.com/JoshBarr/on-media-query