escoliosis24tip

The DOM: What's the Document Object Model?

The DOM is the browser's internal, progrematic representation of a webpage. Languages like javascript allow you to modify the DOM, and thus the website without editing the HTML of the page.

Technically, the DOM is an API (application programming interface). There are many types of APIs, but this particular API interacts with XML and HTML documents. It's in charge of how those documents are accessed and manipulated.

Really, you can do a lot with the dom, and if you're already scripting in JS and jQuery, you're already doing it.

You can insert new things, elements, or alter style or content for elements that already exist.

This can be done with pure javascript, like:
document.getElementById(id)
element.getElementsByTagName(name)
document.createElement(name)

You can also use libraries like jQuery to simplify, standardize and automate manipulating the DOM, like:
$(' #box2').append("This will be added to box2!")

Info and mini-lesson on the 'Console' tab of Chrome Dev Tools. Check out more in-depth documentation here: https://developers.google.com/web/too...

The Console panel provides two primary functions: logging diagnostic information in the development process and
providing a shell prompt which can be used to interact with the document and DevTools.

When using the console, you can view raw or structured data by using standard JS statements and console-specific commands.

An example of structured data would be the information returned from an API in JSON. I used this a lot when I was building my first ziplines for Free Code Camp.

You should know that messages stack up, and you can clear them by typing and entering 'clear()'. You can also save the log by selecting 'Preserve Log'.

There are different commands that will log differently, like console.log() for basic logging, console.error() & console.warn() for "eye catching stuff".

The console can track exceptions, which basically means when something goes wrong. It can even pause the code during those exceptions, a function that you might remember from the 'Source' tab.

JavaScript's Math object overview, as well as a brief heads-up on floating-point formula.

There is a static object named 'Math' in JS with many built in properties and methods.

You'll want to investigate this further whenever you're manipulating numbers. Check here before writing your own functions, because they may already be defined here.
https://developer.mozilla.org/en-US/d...

Examples include Math.random() which will return a random number in a given range and Math.round() which will round the input to the nearest integer. I used Math.random() when I built the random quote generator for the Free Code Camp zipline.

When you're working with numbers, you should also be aware that JS has an interesting attribute called "floating-point format". Depending on the amount of numbers, the size of those numbers, and the number of computations, JS may return something that is inaccurate by .00004. There are ways around this, and in general it doesn't pose issues, but it's something you should be aware of in the event you run into some problems that aren't making sense.

We talk about:
- Simplified portfolio pages
- Code storage in local storage
- Infinite Loop protection
- Camper News improvements
- Creative Commons licensing on everything
- Bonfire Hint system
- New Chat rooms

http://FreeCodeCamp.com is a community of busy people who learn to code, then practice by building projects for nonprofits. Learn Full-stack JavaScript, build a portfolio, and get great references with our open source community.

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