Do web browsers use separate executional threads for JavaScript in iframes?
I believe Chrome uses separate threads for each tab, so I am guessing that JavaScript in an iframe would share the same thread as its parent window, however, that seems like a security risk too.
See Question&Answers more detail:os
Recently tested if JavaScript running in a iFrame would block JavaScript from running in the parent window.
iFrame on same domain as parent:
iFrame on different domain as parent
parent.html:
<body>
<div id="count"></div>
<iframe src="./spin.html"></iframe>
<script>
let i = 0;
let div = document.getElementById("count");
setInterval(() => {
div.innerText = i++;
}, 100);
</script>
</body>
spin.html:
<body>
<button id="spin">spin</button>
<script>
const spin = document.getElementById("spin");
spin.addEventListener('click', () => {
const start = Date.now();
while (Date.now() - start < 1000) { }
})
</script>
</body>
