Why does the iFrame loading page refresh?

In web development, iFrame is a very commonly used tag. It can embed the content of other pages and operate through JavaScript. However, many developers often encounter a problem when using iFrame to load pages: the page will refresh when loading. There are many solutions to this problem, and this article will introduce one of the more common solutions.

First of all, we need to understand why the iFrame loading page refreshes. Normally, when we use iFrame to load a new page, if the page contains JavaScript code, these codes will be executed when the page is loaded, and executing these codes may cause the page to be reloaded. This is because these codes may modify the DOM structure of the page or send requests to the server, etc. These operations may cause the page to refresh.

To solve this problem, we can use two methods. One is to use JavaScript in an iFrame, and the other is to use JavaScript in the embedded page. Below we will introduce the implementation of these two methods respectively.

1. Using JavaScript in iFrame

To use JavaScript in iFrame, we need to add the onload event to the iFrame and execute the page that needs to be loaded in the onload event. For example, the following code:

<iframe src="loading.html" onload="loadPage()"></iframe>
<script>
function loadPage() {
  document.getElementById('iframe').contentWindow.location.reload(true);
}
</script>

In the above code, we added the onload event to the iFrame and executed the loadPage() function in the event. This function will obtain the window object in the current iFrame through the iFrame's contentWindow property, and then load the page through the location.reload() method. Since the true parameter is passed in when calling the location.reload() method, it means that the page is forced to be refreshed, so the page will not be loaded repeatedly.

2. Using JavaScript in the embedded page

To use JavaScript in the embedded page, we need to use the window object of the parent page to operate the iFrame. For example, the following code:

<script>
function loadPage() {
  var iframe = window.parent.document.getElementById('iframe');
  iframe.contentWindow.location.replace('loading.html');
}
</script>

In the above code, we obtain the window object of the parent page through window.parent, and obtain the DOM object of the iFrame in this object. Then we use the location.replace() method to load the new page. This method is similar to the location.reload() method in that it can reload the page, but it will not leave a record in the browser history.

Summary:

The above are two methods to solve the problem of iFrame loading page refresh. You can choose one of them according to your actual situation. No matter which method is used, the key lies in the writing of the code, which needs to make reasonable use of the characteristics of JavaScript to avoid repeated loading.

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