<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div id="target" style="height: 200px; width: 600px;aqua; display: none;"></div>
<div id="test" style="position: relative; display: block;" class="show">test</div>
<script type="text/javascript">
var MutationObserver = window.MutationObserver || window.WebKitMutationObserver || window.MozMutationObserver;
var element = document.querySelector('#test');
var target = document.querySelector('#target')
var observer = new MutationObserver(function (mutations) {
mutations.forEach(function (mutation) {
if (mutation.type == "attributes" ) {
console.log(mutation.target.style.display);
if(mutation.target.style.display == 'none'){
testing.style.display = 'none'
}else{
testing.style.display = 'block'
}
}
});
});
observer.observe(element, {
attributes: true
});
</script>
</body>
</html>