The illustration below shows this relationship: Note that the 'I' in selected Index needs to be capitalised - Java Script functions and variables are always case-sensitive. Read more about the humble checkbox in our HTML5 Checkbox Validation article.
Radio buttons are implemented as if they were an array of checkboxes.
These pages will show how to process PHP forms with security in mind.
Proper validation of form data is important to protect your form from hackers and spammers!
Normally you would modify this so that you could submit or not submit the form based on the number of items selected. Note that in this section we've been using the new ES6 syntax which may not be available in all browsers.To find out which value (if any) has been selected, you need to loop through the array until you find which one has been selected: defines a locally scoped variable.If you're working with arrays of checkboxes to submit data to a server-side script then you might already have some grey hairs from trying to figure out how to validate the input using Java Script.It explains some of the code examples above as well as introducing more advanced concepts: We would be remiss in not pointing out that your Java Script and HTML code should be kept separated as far as possible. I've coded a working form, all checks are great but for some reason the hardest part is trying to stop form submission before validation.So i have places to insert the stop validation code, but just cant find any that works.