问题
Trying to troubleshoot some design issues on a website (built with OpenCart), and ran into an issue I've never seen before: an element shows up in Dev Tools but DOESN'T show up in View Source.
How is this possible? And how can I find the actual element?
The situation is, I had to modify the original template (category.twig) to change the "Add To Cart" button to "View"... and it works in the default category view, but as soon as any of the filters are selected, this happens... it reverts to the original view.. but it's still the same file (I added the path into the code itself, just to make sure I'm indeed looking at the same file, you can see in in the Code View portion of the screenshot).
So yeah... trying to trace where this "Add To Cart" is coming from, and being mighty confused as so why it's NOT showing up in View Source. And no, there's no JavaScript targeting the "view_button" DIV and transforming it into "Add To Cart" - I made the "view_button" DIV, it's custom.
Any advice?
回答1:
Javascript can (and often does) create new elements in the document, that won´t appear on code view becasuse it does not execute javascript. I would advice you to download the entire page and then search for button-cart-text in js files or the whole document.
回答2:
The document's source does not define the element statically, but the JavaScript creates the element dynamically. This is very common. The dev. tools show you the document as it exists in memory (it's current state), which will include anything that the JS caused to happen, but view...source shows you the actual source code of the static file that was initially loaded.
回答3:
Source code is what the programmer wrote. Or, in the case of "View Source" in a browser, it is at least what the server responded with, which may have been written by hand or may be generated using various forms of compilation or bundling. A common example here would be a page rendered from templates (e.g. using Handlebars).
Live code, or at least live markup, is what you are seeing in the Elements pane in the browser console. You are seeing the DOM rendered in realtime, right before your very eyes. You are watching the program (i.e. the page and its subresources) execute and take effect. It is mutating, most likely due to JavaScript.
For extremely simple pages like example.com, the difference between the source code and the live code may be imperceptible, because nothing is modified at runtime. However, for more complex, real-world websites, the DOM is often modified while you are browsing the page so that it can respond to your clicks, your typing, or anything else. These modifications are extremely powerful and useful. However, as you have discovered, they make the source code and the live code diverge. This makes a programmer's life more difficult, while making a user's life easier.
来源：https://stackoverflow.com/questions/46899967/element-present-in-chrome-dev-tools-but-not-in-view-source-how-is-this-possibl