Specifying content of an iframe instead of the src attribute to a page_问答_开发者

Specifying content of an iframe instead of the src attribute to a page

开发者 https://www.devze.com 2023-01-25 16:34 出处：网络

I\'m currently working on a form which includes some file inputs to upload pictures. There is an onchange() event for those inputs that submits the pictures to an iframe, 开发者_运维问答then dynamical

相关专题：iframe

I'm currently working on a form which includes some file inputs to upload pictures. There is an onchange() event for those inputs that submits the pictures to an iframe, 开发者_运维问答then dynamically loads the uploaded pictures into the form, with fields to be modified for them (like name and geo-localization).

Since I can't nest forms, the file_input is also contained in an iframe. In the end I use an iframe inside of another iframe. So I have something like this:

<form>
<!-- LOTS OF FIELDS!! -->
<iframe src="file_input_url">
<!-- iframe which loads a page of a form with a file input-->
</iframe>
</form>

and the HTML loaded into the iframe is something like (excluding the html, head and body tags)

<form target="upload_iframe">
<input type="file" onchange="this.form.submit()">
</form>
<iframe name="upload_iframe"></iframe>

This works great, except for the fact that it takes a couple seconds to load the first iframe, so the file input does not load with the rest of the page. This is not visually ideal. I could solve it if I could specify the iframe content without needing to load another page (specified by file_input_url in the first iframe).

Is there a way to specify the iframe content in the same document, or can it only be specified with the src attribute, requiring the load of another page?

You can .write() the content into the iframe document. Example:

<iframe id="FileFrame" src="about:blank"></iframe>

<script type="text/javascript">
   var doc = document.getElementById('FileFrame').contentWindow.document;
   doc.open();
   doc.write('<html><head><title></title></head><body>Hello world.</body></html>');
   doc.close();
</script>

iframe now supports srcdoc which can be used to specify the HTML content of the page to show in the inline frame.

You can use data: URL in the src:

var html = 'Hello from <img src="http://stackoverflow.com/favicon.ico" alt="SO">';
var iframe = document.querySelector('iframe');
iframe.src = 'data:text/html,' + encodeURIComponent(html);

<iframe></iframe>

Difference between srcdoc=“…” and src=“data:text/html,…” in an iframe.

Convert HTML to data:text/html link using JavaScript.

In combination with what Guffa described, you could use the technique described in Explanation of <script type = "text/template"> ... </script> to store the HTML document in a special script element (see the link for an explanation on how this works). That's a lot easier than storing the HTML document in a string.