Where to Discuss?

Preface

Goal: Explaning how to inspect HTML document.

This is also should be, an easy task to do. But I found that many beginner don’t know how to examine HTML, and of course change stylesheet behaviour. So I decide to make this short article, using our last example.


Other Browser Tools

This is a must have knowledge

Before inspecting Element consider see built tools that your browser might have have.

First, open the previous example, using browsersync in localhost:3000.

Browser Tools: HTML Page

Source Code

If you are using Firefox, you can press Ctrl+U to show source code. This is very useful if you work with backend or SSG (static site generator).

Browser Tools: Source Code

Chromium has similar feature.

Meta

If you are using Firefox, you can press Ctrl+I to show meta header. This looks silly when you have a few meta, but you are going to need this feature, once you had many meta such as opengraph, twitter and such SEO stuff.

Browser Tools: Meta Header


Inspect Element

You can open inspect element from context menu.

Browser Tools: Meta Header

And you can either dock the inspect element within the browser, put let the inspect element be separate window.

HTML

Consider see the result if click the red alert, and inspect the element.

Inspector: Element

Stylesheet

One of the most useful thing in element inspector is, we can change the stylesheet behaviour in a live page. It means, we don’t need to change the source code. Nor we need to refresh the page.

Consider have a look at the source code of the previous example:

.red {
  color: #fff !important;
  background-color: #f44336 !important;
}

Now consider changing the value in inspect element. Change the color of the text of the red alert, from white fff to yellow ff0!

Inspector: Change Color Element

And see the result as below:

Browser: Result of the Color Change

Javascript

How about the Javascript? Remember the old days when people use pop-up alert( ... )? Now we have console.log( ... ).

Consider have a look at the unobtrusive javascript below:

document.addEventListener("DOMContentLoaded", function(event) { 
  var alertButtons = document.getElementsByClassName("dismissable");
    
  for (var i=0; i < alertButtons.length; i++) {
    alertButtons[i].onclick = function() {
      this.parentElement.style.display='none';
      console.log('Close Button. Element ' + this.parentElement.id + ' dismissed');
      return false;
    };
  };
});

And also how the trigger be done in HTML code, by just defining the dismissable class.

    <div class="panel red display-container" id="red-danger">
      <span class="dismissable button large display-topright">&times;</span>
      <p><strong>Danger!</strong>:
        Red often indicates a dangerous or negative situation.</p>
    </div>

    <div class="panel yellow display-container" id="yellow-warning">
      <span class="dismissable button large display-topright">&times;</span>
      <p><strong>Warning!</strong>:
        Yellow light indicates that something could go wrong.</p>
    </div>

    <div class="panel green display-container" id="green-success">
      <span class="dismissable button large display-topright">&times;</span>
      <p><strong>Success!</strong>:
        Green light indicates on schedule, on budget, all good.</p>
    </div>

    <div class="panel blue display-container" id="blue-info">
      <span class="dismissable button large display-topright">&times;</span>
      <p><strong>Info!</strong>:
        Blue light indicates that you are in electronics mode.</p>
    </div>

Now, consider click x in each alert box. We are going to see the result in console.

Inspector: Javascript Console

Other Feature

There are some other feature, but this is beyond the scope this tutorial for beginner.

For example, you can try this network tab yourself. This is useful to track if there are any asset that failed to be loaded.

Inspector: Network

I think that is all.


What’s Next?

Consider continue reading [ Tools - HTML - Pug ].