17 lines
728 B
JavaScript
17 lines
728 B
JavaScript
function generate_parallax_element( selector, context ) {
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context = context || document;
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var elements = context.querySelectorAll( selector );
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return Array.prototype.slice.call( elements );
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}
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window.addEventListener( "scroll", function() {
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var scrolledHeight= window.pageYOffset;
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generate_parallax_element( ".parallax-enabled" ).forEach( function( el, index, array ) {
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var limit = el.offsetTop + el.offsetHeight;
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if( scrolledHeight > el.offsetTop && scrolledHeight <= limit ) {
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el.style.backgroundPositionY = ( scrolledHeight - el.offsetTop ) / el.getAttribute( 'data-parallax-speed' ) + "px";
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} else {
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el.style.backgroundPositionY = "0";
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}
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});
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}); |