javascript style observer

styleObserver.js

var styleObserver = new MutationObserver(function(mutations) {
    mutations.forEach(function(mutationRecord) {
        var computedStyle = window.getComputedStyle(target, null);
        console.log(mutationRecord);
        if (mutationRecord.target.style.display == 'block') {
            console.log('block!');
            mutationRecord.target.focus();
        }
    });
});


// By class name
var targets = document.getElementsByClassName("modal");
var i;
for (i = 0; i < targets.length; i++) {
    styleObserver.observe(targets[i], { attributes : true, attributeFilter : ['style'] });
}

// By id
var target = document.getElementById('embed-{{ resource_view['id'] }}');
styleObserver.observe(target, { attributes : true, attributeFilter : ['style'] });