обозначение required true в input

input type="text" id="car" required="true" /> - is wrong

, it should be one of:
input type="text" id="car" required />
input type="text" id="car" required="" />
input type="text" id="car" required='' />
input type="text" id="car" required=required />
input type="text" id="car" required="required" />
input type="text" id="car" required='required' />

отсюда: http://stackoverflow.com/questions/3090369/disable-validation-of-html5-form-elements