Making your web forms responsive is not a topic that's discussed too often. Mostly because it's not a huge deal to get HTML form elements to behave in a responsive manner – that is, to be both liquid and to utilise targeted screen widths with media queries to serve up specific form layout changes.
The main thing is to consider the context in which a person will be using the form. This a question of thinking through the device you are targeting, not just its screen size. Let's look at a couple of examples that help illustrate my point.
First, field sizing is important on smaller screens when people are using their fingers to target a form field. When using our phone, we do not have the same level of precision as we do with a mouse. Apple's Human Computer Interaction Design documentation has some great in-depth information on how to design for people who are using their fingers to interact with a device.
Another consideration when designing a responsive layout is the placement of form elements in relation to their respective fields. On desktops and iPads, having the labels left-aligned makes the form appear simple to complete.
If we change the same form on an iPhone's screen so the labels are on top of the fields, this makes the user slow down a little. As mobile users often have their attention split between different tasks, this should help focus their efforts. Accuracy is more important than speed.
Here are some examples:
Words: Gene Crawford
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