javascript 懒惰的BGSet

Posted 2021-05-03

$(document).ready(function() {
    lazysizes_bgset();
    
    $(window).resize(function() {
        lazysizes_bgset();
    });
    
});

function lazysizes_bgset() {
    var vpWidth = viewport().width;
    $('.lazyload-bgset').each(function() {
        var element = $(this);
        if( element.attr('data-bg-lg') && vpWidth > 1024 ) {
            if( !element.hasClass('lg-loaded') ) {
                var lg_url = element.data('bg-lg');
                element.attr('data-bg', lg_url).addClass('lazyload lg-loaded').removeClass('md-loaded xs-loaded');
            }
        }else if( element.attr('data-bg-md') && vpWidth > 768 ) {
            if( !element.hasClass('md-loaded') ) {
                var md_url = element.data('bg-md');
                element.attr('data-bg', md_url).addClass('lazyload md-loaded').removeClass('xs-loaded lg-loaded');
            }
        }else if( element.attr('data-bg-xs') ) {
            if( !element.hasClass('xs-loaded') ) {
                var xs_url = element.data('bg-xs');
                element.attr('data-bg', xs_url).addClass('lazyload xs-loaded').removeClass('md-loaded lg-loaded');
            }
        }
    });
}