jQuery 1.10.1, HTML, CSS, JavaScript
No-Library (pure JS), HTML, CSS, JavaScript
jQuery (edge), HTML, CSS, JavaScript
Bootstrap sample
using readonly-attribute and remove it on focus (touch, tab, click)
jQuery 2.2.4, HTML, CSS, JavaScript
Validates that at least one of four fields must be validated. If one is, it's assumed the group of fields is valid and the form can be submitted
jQuery 2.0.2, HTML, CSS, JavaScript