Validating checkbox

(note that the form method is post in the HTML form).To make it a bit cleaner, we can trim the input to remove any extra space from the beginning and end of the form.I would like to show an alert if no check box was checked in a field.The idea is that at least one check box should be checked.From that you should be able to figure out what the problem is with your IF condition.

If this happens an error is returned: "Element CHECKBOX is undefined in FORM." Could anyone tell me how I could validate the form to make sure that people using it tick at least one checkbox. Here is the PHP script that checks the name for empty input and throws an error if the input is empty.When we display the form back again, it should not loose the form data the user already had filled-in.Basically you don't want the form to be submitted unless this is checked.Using vanilla Java Script we can prevent form submission as follows: All this does is confirm before submitting the form that the checkbox is checked.So we have to display the value from the $_POST in the input value attribute.Note that we are using the htmlentities() function to encode any HTML entities like checks whether Round6 was selected.I've spent a couple of hours searching for a solution to validating a checkbox, since the Required Field Validator does not work with Checkboxes. Look for "skm Validators - custom validation controls for Check Boxes and Check Box Lists Actually I like to use AJAX for Checkbox validation, if you add the checkboxes inside an Update Panel and then on the server side you can check if they are check or not and update a red label by the checkbox.To the user, looks like works the same way the validation, for you, is just a little bit more magic to write.It is also required to add server side form validation in your form processing script.The user can disable Javascript on their server or even auto-bots might try to submit your form as well.

68 comments

  1. Simple JavaScript Checkbox Validation. Ask Question. up vote 12 down vote favorite. 3. I usually work with PHP so sadly don't have some basic JS principles down.

  2. Hi, I am trying to validate a checkbox selection but my code doesn't work. Here is the code I have form action="form.php" method="post.

  3. Instructions and examples for validating checkbox elements using HTML5, JavaScript and CSS3

  4. PHP Form Validation Tutorial. PHP Form, Tutorials. Validating a checkbox group. Check box groups are great when you want to allow multiple options for a field.

  5. I have a form created dynamically from a database. Folk using the form select several of the checkboxes and submit the form. cfquery

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