If you have access to manipulate the code of the site you are loading, the following should provide a comprehensive method to updating the height of the iframe container anytime the height of the framed content changes.
Add the following code to the pages you are loading (perhaps in a header). This code sends a message containing the height of the HTML container any time the DOM is updated (if you're lazy loading) or the window is resized (when the user modifies the browser).
window.addEventListener("load", function(){
if(window.self === window.top) return; // if w.self === w.top, we are not in an iframe
send_height_to_parent_function = function(){
var height = document.getElementsByTagName("html")[0].clientHeight;
//console.log("Sending height as " + height + "px");
parent.postMessage({"height" : height }, "*");
}
// send message to parent about height updates
send_height_to_parent_function(); //whenever the page is loaded
window.addEventListener("resize", send_height_to_parent_function); // whenever the page is resized
var observer = new MutationObserver(send_height_to_parent_function); // whenever DOM changes PT1
var config = { attributes: true, childList: true, characterData: true, subtree:true}; // PT2
observer.observe(window.document, config); // PT3
});
Add the following code to the page that the iframe is stored on. This will update the height of the iframe, given that the message came from the page that that iframe loads.
<script>
window.addEventListener("message", function(e){
var this_frame = document.getElementById("healthy_behavior_iframe");
if (this_frame.contentWindow === e.source) {
this_frame.height = e.data.height + "px";
this_frame.style.height = e.data.height + "px";
}
})
</script>