get element infromation from a page that use javascript

Question

in a browser such as google chrome , when I want to get information of the page , I just select view page source but in some sites that use javascript you cant do that , so I discovered that on any element such as a button and select inspect element it will show me the information that I need , and its really great but I want to do this automatically for example for simple pages that use html , I just use wget to save the page to text to analyze it later , but for pages that use javascript and css its impossibile , so my question is there a tool or any way to get the information I need and save it to text lets say I specify the site and the element (button ) and it will download the code and will save it to text

Answer 1

If you use chrome, you can do Ctrl + Shift + J to get the Developer tools window open. Click the Top left most icon (Elements) to see the DOM as it stands after JavaScript modification.

In IE (7 or above I think) use F12 to open a similar window.

And in FireFox you can use Ctrl + Shift +I to open a similar window.

And for automating this process try using http://www.phantomjs.org/ (as suggested here: wget + JavaScript?)

Edit:

There is a Save button in IE which saves the current DOM:

In FireFox after you have pushed Ctrl + Shift + I press Ctrl + S and it will save the current DOM.

Edit 2:

Download PhantomJS, create a file called script.js paste this into it:

system = require('system');
var page = new WebPage();
page.open(system.args[1], function (status) {
    if(status == 'success') {
        html = page.evaluate(function() {
            return document.getElementsByTagName('html')[0].innerHTML;
        }); 
        console.log(html);
    } else {
        console.log('Page could not be loaded');
    }
    phantom.exit();
});

Run phantomjs script.js http://www.website.co.uk > website.html at the comment line (script.js and phantom.exe will have to be in the current working directory). Change http://www.website.co.uk to the website you need to download and website.html so the`html file you want to save to.