Simple way to lazyload iframes.

iframe-lazyload.js

/**
 * Simple way to lazyload iframes.
 * 
 * Add class of 'lazyload' to iframe and change
 * the 'src' attribute to 'data-src'
 */
jQuery(function($) {
    function isVisible(element) {
        var element = element.getBoundingClientRect()
        
        return element.top < window.innerHeight && element.bottom >= 0
    }
    
    $(window).on('scroll', function() {
        $('.lazyload').each(function() {
            if (isVisible($(this)[0])) {
                $(this).attr('src', $(this).attr('data-src')).removeClass('lazyload')
            }
        })
    }).trigger('scroll')
})

iframe-lazyload.min.js

/**
 * Simple way to lazyload iframes.
 * 
 * Add class of 'lazyload' to iframe and change
 * the 'src' attribute to 'data-src'
 */
jQuery(function(t){function n(t){return(t=t.getBoundingClientRect()).top<window.innerHeight&&t.bottom>=0}t(window).on("scroll",function(){t(".lazyload").each(function(){n(t(this)[0])&&t(this).attr("src",t(this).attr("data-src")).removeClass("lazyload")})}).trigger("scroll")});