Adding Client Side validation to Login and Registration Forms

Its very important to have a client side validation apart from a server side validation. The server side validation only helps the developers but not the clients. Thus it was necessary to add a client side validation to the Login page and its other components so that the usersĀ  would be comfortable in this.

I had never before done this and was looking at how to achieve this using jQuery or JavaScript when I cam to know that we were already using an amazing validation tool : Bootstrap Validator

It just involves wrapping the form in the html with the validator plugin and all the checks are automatically carried out by it.



As you can see in the above image, we have just added a data-toggle=”validator” line to the form which automatically wraps the form with the plugin. The above form is the Create New Password form which checks whether the new password and the password entered again are matching or not. If not then the line ,


checks it with the password in the new_password field and gives an error on the page to the client defined by the following,

data-error="Passwords do not match

Thus adding such checks to the form becomes very simple rather than using jQuery for it. Similarly it was important to add validation to the Register page.

 <input type="email" name="email" class="form-control" id="email" 
 placeholder="Email" data-remote="{{ url_for('admin.check_duplicate_email') }}"
 data-remote-error="Email Address already exists" required="">

This is the validation for the email field. Apart from checking whether the text entered by the user is an email id or not it was also important to check whether the email entered by the user exists in the database or not.

data-remote="{{ url_for('admin.check_duplicate_email')

This line calls a view function to check whether the email entered by the user is duplicate or unique. Here is the function


This function takes the email value from the request.args and then performs a simple check in the db to check for duplicate email. If the user doesnt exist then the validator receives a simple string “200 OK”. If the error is 404 then it gives the error defined by,

data-remote-error="Email Address already exists"

However this error only for the data-remote part. If the error is something else then it is handled by ,

class="help-block with-errors"

Thus without the hassle of using Ajax and JQuery we can easily add validation to the forms using Bootstrap Validator.

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