How do we get out of the way of the user?
There are two approaches you can take to putting the user in control of text sizes:
- Don't attempt to set the size of your text at all.
- Or, set the size of text in your web pages using a relative unit of measurement.
By choosing the first option, i.e. abandoning any attempt to control the size of text on the pages you design, you are also removing any barriers to access - at least those related to text size - you might inadvertently put in the way of your visitors.
However it also means that if your pages may not look as nice as you would like; as they will adopt the users browser preferences and the 'default' HTML style sheet, with, for example, headings that look too big for the surrounding text.
With the use of relative units, you get the best of both worlds; you give the user control of relative text size, and you get to set text sizes that won't offend your aesthetic sensibilities. With this approach, when a user changes the text size in their browser, all of the text on the page gets bigger or smaller, but the relative sizes of the text structures remain the same.
For example, if you think of the main paragraph text as being 100% or the browser default size, a top level heading may be 130%, a sub-heading 120%, text for navigation 95% and so on. (Please note that: these are not recommendations, just examples.)
By using relative units to set the size of text in your Web pages you are recognising that you can't predict the needs of the end user, or the type of output device used.
If the visitor your website wants, or needs the text to be big - they should be able to make it big, just by changing the preferences in their browser. Below are some example of relative units you could use to give your users that ability:
- em units
- percentages
- relative keywords such as smaller or bigger
I will look at how these relative units work in practice shortly, but, first there are a couple of important issues that I feel need to be addressed before we proceed to that discussion.
First there is the argument put forward by Joe Clark, that text size is not a particularly important issue for accessible web designers to concern themselves with, and as long as the text is not set so small it's unreadable, it doesn't matter what unit of measurement you use.
Secondly, it is important that we explore the case against using absolute units (e.g. points) for setting the size of text on web pages - as it is one of the most common accessibility problems that I come accross when auditing pages for accessibility.
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