Inject Javascript code into a web page
Question
I'd like to download web page as html file. Before I save the web page source code in html file, I'd like to edit some of the page content first. I assume I can edit the content using Javascript. Unfortunately I have little experience with Javascript. I guess I have to inject my script into the web page so that the browser can execute them together. How should I write my script? Should I write a standalone script and pass the page url to my script so that they can be executed at the same time? Or there are other ways to inject my script?
3 answers
solution1
2 ACCPTED 2013-01-11 06:57:55
As you are only doing this once, starting your script from the browsers JavaScript console should be enough. Open the developer tools, navigate to the console tab, paste your script content, and press enter.
To get the edited HTML, evaluate the expression document.documentElement.outerHTML in the console. Copy the output to a text editor of your choice, prepend it with a doctype, and save it as html.
solution2
1 2013-01-11 08:01:07
If you want to save modified source as html you can use different aproaches, depends on what you want to mainupulate. Sadly with javascript saveing file is tricky and depends on many things, so you could use option to copy paste file source manually or write your browser and settings specific file saver. I would prefer javascript+php combo solution. Or if there is no need to manipulate someting with javascript i would do it entirely in php.
Step 1 - open browser with console, in chrome and firefox CTRL+SHIFT+J And allow popups. Step 2 - open webpage you want Step 3 - Copy next code to console
//Script loading function
function load_script( source ) {
var new_script = document.createElement('script');
new_script.type = 'text/javascript';
new_script.src = source;
new_script.className = 'MyInjectedScript';
document.getElementsByTagName('head')[0].appendChild(new_script);
}
function escapeHtml(unsafe) {
return unsafe
.replace(/&/g, "&")
.replace(/</g, "<")
.replace(/>/g, ">")
.replace(/"/g, """)
.replace(/'/g, "'");
}
//Load jQuery, if page do not have it by default
if (typeof(jQuery) != 'function') load_script('http://code.jquery.com/jquery-latest.js');
Step 4 - Do your manipulations in console
Step 5 - Copy next code to console
//In the end remove your injected scripts
$('.MyInjectedScript').remove(); //Or jquery script will be in source
//get Document source
var doc_source = $('html',document).html();
doc_source = '<html>'+doc_source+'</html>';
var new_window = window.open('', '', 'scrollbars=yes,resizable=yes,location=yes,status=yes');
$(new_window.document.body).html('<textarea id="MySource">'+escapeHtml(doc_source)+'</textarea>');
STEP 6 - copy paste code from opened window textarea
If you want to do it with PHP you can easily download page with curl and manipulate content and save file as desired.
solution3
-1 2022-02-12 04:47:07
You can use a browser extension like Requestly to Inject custom Javascript/CSS on web pages .
This is how you can do it.
- Download Requestly and Open Rules Page
- Create New Rule and Select Insert Custom Script/CSS Rule Type
- Enter your domain (or Page URL Pattern) and define your Script
Screenshot - Insert Script Rule
If you are looking for a Cross-Browser solution then you can use Requestly Desktop App and Configure your rule similarly.
In your particular case, you can choose an option like to run the script after page load so that all DOM Elements are present on the page before you modify/annotate them.
Disclaimer - I built Requestly
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