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Best practices for classes

From: CSS Web Site Design

Video: Best practices for classes

As a follow on to the previous video I just want to take a minute to talk about a few best practices when it comes to classes. It can be very tempting to over class as it were, to end classes really nearly and I hit her in Jan. Just on the off chance that you might need them some day. As an example here in this document, you can see where we have these list items here that contain links that are navigation links and every one of these list items has a class of navlink and in the a element, inside them have classes of navlinks and this is really, really, really inefficient.

Best practices for classes

As a follow on to the previous video I just want to take a minute to talk about a few best practices when it comes to classes. It can be very tempting to over class as it were, to end classes really nearly and I hit her in Jan. Just on the off chance that you might need them some day. As an example here in this document, you can see where we have these list items here that contain links that are navigation links and every one of these list items has a class of navlink and in the a element, inside them have classes of navlinks and this is really, really, really inefficient.

There's no need for all of this navlinking classing to happen here. Instead, you could just take all that out so that instead of having classes everywhere, you just have these plain elements and then you might wonder to yourself well, how am I supposed to select those. Well, that's coming up later in the chapter, about the short preview answer is that you use the ID up here on the element that encloses all these other elements in order to make your selections.

This sort of drive to class everything in sight is an understandable one, but it's one that needs to be restrained. You can end up loading your documents markup and making it harder to maintain, harder to read, because with all those classes everywhere there's more markup to deal with. Here, it's much cleaner. There's one other thing that can be done with classes and you remember we had first and last perhaps from the last one.

You can actually have multiple words in the same class attribute, so we can have first and we can also have urgent. So not only is this list item in have a class of first meaning that it's the first element of something that's the meaning that we've just decided to give to first, is not that the class name first intrinsically means this is the first element of something else, is just that we're using the name first to mean that and also the name urgent to mean that there's something urgent about this particular bit of information. So what we have here is a list item that's in the class first and also the class of urgent and those can be addressed separately in effect, so we can say li.first background yellow, actually let's make it dot first background yellow.

So any element with the class of frst will have a yellow background and if we go to Firefox and hit Reload, then we can see that indeed we have yellow backgrounds for all the elements that have a class of first, but we can also say, any element with a class of urgent, will italicize. So now when I hit Reload, the, the text about us is in italics, because both of those selectors both of those class selectors match this particular elements class and the order these are in, actually doesn't matter.

So the fact that we have urgent and then we have first, the order that these were joined in this class value doesn't matter. It doesn't make a difference in terms of what the order is up here. Now, the order the styles are in a style sheet can matter, but we'll talk about that in a video leader in this particular Chapter. That's one thing that you can do with classes. It's not a common need it's not like you'll be doing this what's sometimes called multiclassing, every time you write a document. But the times, that you do need it, it comes in very handy.

One classic example is if you're creating a portal page and the portal has little boxes in it that have different bits of information in different forms, each one of those might be rapped in a div, but the widgets that allow user input of some kind for example, a weather box, where the user can input their zip code and get the local weather, you can have that div class equals widget and then a space and then user input or input allowed, or you know, whatever class that makes sense to you and then have a rule that styles all the little widgets with, you know, put a little border around them and whatever else you want to do, but then with the class of input allowed, or user input, you can change just certain aspects of how those particular widgets are presented that the border is red and thicker, or there's a different background color on that particular widget. So, that's the sort of situation in which multiclassing can come in very handy.

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This video is part of

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CSS Web Site Design

73 video lessons · 60888 viewers

Eric Meyer
Author

 
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  1. 14m 34s
    1. Welcome
      28s
    2. What is CSS?
      5m 34s
    3. Design tour
      2m 38s
    4. Using the exercise files
      1m 20s
    5. Installing the Web Developer toolbar
      4m 34s
  2. 25m 56s
    1. XHTML essentials
      3m 55s
    2. CSS essentials
      5m 17s
    3. Embedded style sheets
      2m 20s
    4. Linking a style sheet
      2m 19s
    5. Linking to multiple style sheets
      2m 20s
    6. Using linked and embedded style sheets together
      4m 21s
    7. Using imported style sheets
      5m 24s
  3. 57m 48s
    1. ID selector essentials
      6m 38s
    2. Class selector essentials
      4m 9s
    3. Best practices for classes
      4m 52s
    4. Grouped selection
      4m 2s
    5. Descendant selectors
      6m 44s
    6. The sources of style
      6m 38s
    7. Specificity
      8m 21s
    8. Making things important
      4m 32s
    9. Inheritance essentials
      5m 12s
    10. Making things really unstyled
      4m 2s
    11. User style sheets
      2m 38s
  4. 39m 3s
    1. Box model essentials
      7m 35s
    2. Simple floating
      5m 3s
    3. Using float for layout
      5m 5s
    4. Fixing column drop
      5m 35s
    5. Clearing essentials
      4m 20s
    6. Float containment
      6m 35s
    7. Creating a navbar from a list
      4m 50s
  5. 38m 3s
    1. Coloring text
      4m 13s
    2. Defining color in CSS
      8m 12s
    3. Coloring backgrounds
      6m 35s
    4. Applying background images
      4m 19s
    5. Manipulating the direction of background images
      2m 52s
    6. Positioning backgrounds
      7m 23s
    7. Background shorthand
      4m 29s
  6. 58m 28s
    1. Altering line height
      7m 32s
    2. Font style and weight
      5m 45s
    3. Sizing fonts
      9m 59s
    4. Using font families
      10m 38s
    5. Font shorthand
      6m 5s
    6. Justifying text
      4m 56s
    7. Vertically aligning text
      4m 22s
    8. Transforming text
      3m 49s
    9. Text decoration
      5m 22s
  7. 44m 40s
    1. Margin essentials
      14m 21s
    2. Adding borders
      6m 52s
    3. Padding
      9m 17s
    4. Using negative margins
      7m 19s
    5. Margin collapsing
      6m 51s
  8. 20m 38s
    1. Styling tables and captions
      5m 23s
    2. Styling table cells
      6m 30s
    3. Styling a column with classes
      4m 51s
    4. Styling links inside table cells
      3m 54s
  9. 30m 40s
    1. Styling for specific mediums
      4m 3s
    2. Creating a print style sheet
      6m 35s
    3. Hiding layout for print
      4m 11s
    4. Styling for print
      6m 34s
    5. Complex styling for print
      4m 37s
    6. Creating a footer
      4m 40s
  10. 37m 23s
    1. Getting started
      1m 11s
    2. Setting global styles
      4m 4s
    3. Defining masthead and navbar colors
      3m 27s
    4. Layout of the navlink bar
      3m 38s
    5. Using columns
      4m 49s
    6. Setting content styles
      1m 53s
    7. Creating the sidebar boxes
      5m 42s
    8. Creating the sidebar form
      3m 23s
    9. Completing the sidebar
      3m 29s
    10. Making a table
      3m 12s
    11. Creating a footer
      2m 35s
  11. 1m 28s
    1. Goodbye
      1m 28s

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