To call a parent window function, use “window.top”.
Example
You can try to run the following code to call a parent window function from an iframe
Live Demo
<!DOCTYPE html>
<html>
<body>
<script>
function display(){
alert("Hello World!");
}
</script>
<iframe id="myFrame">
<a onclick="window.top.display();" href="#">Click</a>
</iframe>
</body>
</html>