CAUTION

 One thing to watch out for: when you specify units in CSS, you must leave no spaces between the number of units and unit specification. In other words, 12pt and 100% are valid,  and 12pt and 100%aren’t

There’s another thing that you can be do with the font-size property that’s not possible with the <font> tag: line height. Let’s not possible with the <font> tag: specify line height. Let’s say you want to use double-spaced text on your page. Before CSS, the only way to achieve the effect was to use the <br>in this manner can look truly awful. To set the line height using CSS, you can include it in you font size specification, like this: font-size: 100/200%. In this case, the size of the font is 100%-the default-and the line height is 200% twice the standard line height.

DO

Do specify fonts using CSS rather than the <font> tag.

Do list backup fonts when specifying a font family order to make it more likely that your users will have one of the fonts you specify.

DON’T

Don’t use too many different fonts on the same page.

Don’t use absolute font sizes with CSS if you can help it, because some browsers won’t let users alter the text size if you do so.

<NOBR> AND <WBR>

DO DON’T TIP

 Do design your pages so that they work in most browser.

Do focus on clear, well-structured content that’s easy to read and understand.

DON’T

Don’t design your pages base on what they look like on your computer system and on your browser.

Throughout this book, I’ll show you examples of HTML code and what they look like when displayed. In examples in which browsers display code very differently, I’ll give you a comparison of how a snippet of code looks in tow very different browses. Through these examples, you’ll get an idea for how different the same page can look from browser to browser.

TIP

Although this rule of designing by structure and not by appearance is the way to produce good HTML, when you surf the web, you might be surprised that the vast majority of websites seem to have been designed with appearance in mind-usually appearance in a particular browser such as Microsoft internet explorer. Don’t be swayed by these designs. If you stick to the rules I suggest, in the end, you web pages and websites will be even more successful. Simply because more people can easily read and use them.