We'll do this by adding a listener for the class, we'll get every field, loop through each one, and check for errors.We'll store the first invalid field we find to a variable and bring it into focus when we're done.Even when validation is supported perfectly, there may be times when custom validations are needed and a more manual, Vue-based solution may be more appropriate. Beneath that there is a paragraph that shows or hides itself based on an error state.This will render a simple list of errors on top of the form.// If too short if (Short) return 'Please lengthen this text to ' Attribute('min Length') ' characters or more.You are currently using ' field.value.length ' characters.'; // If too long if (Long) return 'Please short this text to no more than ' Attribute('max Length') ' characters.Our finished script weight just 6kb (2.7kb minified). It works in all modern browsers and provides support IE support back to IE10. Here's the good news: with a lightweight polyfill (5kb, 2.7kb minified) we can extend our browser support all the way back to IE9, and add missing properties to partially supporting browsers, without having to touch any of our core code.Form validation is natively supported by the browser, but sometimes different browsers will handle things in a manner which makes relying on it a bit tricky. Let’s look at the HTML first: is a temporary URL that would point to something real on a server someplace (where you have backup server-side validation of course).
Once we show an error, your visitor will (hopefully) fix it.
If the field is a radio button or checkbox, we need to change how we add our error message to the DOM.