A form is "dirty" if any of its field has changed since:
- it was loaded
- or it was last reset
- or it was last submitted
When the form is dirty:
<inform-el dirty />.
document.querySelector("inform-el").dirty; // true
The example below uses the dirty attribute and CSS to show a warning only when the form is dirty:
Try changing the first name: the warning appears. Try setting the first name back to "changeme": the warning disappears!