It is very important for visually impaired users of iPhones to have the ability to scale all web pages. Without this they will have a hard time reading your site.
Google is almost impossible for me to use because they are not allowing the page to zoom in and out. Don’t make this mistake in your web application for the iPhone!
If you use:
<meta name="viewport" content="width=320; initial-scale=1.0; maximum-scale=1.0; user-scalable=0;">
When developing an iPhone web application your page will not be scalable for people with vision impairments.
<meta name="viewport" content="width=320; initial-scale=1.0; maximum-scale=20.0; user-scalable=1;">
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