Google reCaptcha 2 JavaScript Validation (client side)
reCaptcha is a great “bot” detection solution from Google. Google watches the pattern of user interaction to decide whether it is a “bot” or a real user. It is near impossible for a “bot” to simulate those patterns. So reCaptcha succeeds in blocking spam most of the time. Versions of reCaptcha reCaptcha version 1 reCaptcha version 1 used to show a couple of words in an image and the user had to enter the words in a box to prove they are not “bots”.
Checkbox checked validation using JavaScript
You can check whether a checkbox is checked or not using checkbox_elemnt.checked attribute. Here is an example: See the Pen single checkbox validation by Prasanth (@prasanthmj) on CodePen. Here is the JavaScript code for easy reference: function validateForm(form) { console.log("checkbox checked is ", form.agree.checked); if(!form.agree.checked) { document.getElementById('agree_chk_error').style.visibility='visible'; return false; } else { document.getElementById('agree_chk_error').style.visibility='hidden'; return true; } }
Checkbox validation using jQuery
Suppose you have a check box with ID agree_checkbox. You can check whether the checkbox is checked using this jQuery code: $('#agree_checkbox').prop('checked') Here is a complete example: See the Pen Checkbox validation using jQuery by Prasanth (@prasanthmj) on CodePen. Here is the code that does the check: $("#myform").on("submit",function(form) { if(!$("#agree_checkbox").prop("checked")) { $("#agree_chk_error").show(); } else { $("#agree_chk_error").hide(); } return false; })
How to do multiple checkbox validation in Javascript
Checkboxes can be used as a single checkbox (like an on-ff switch) or as a group of checkboxes where the user can select one or more options. How do we do validations when you have multiple checkboxes? Here are some samples. At least one checkbox should be checked (Required validation) See the Pen Multiple checkbox validation by Prasanth (@prasanthmj) on CodePen. In the validation code, we extract the FormData object from the form element.