Mail alerts module help with form validation

[CPTBombaxx]

Hello, 

we use native mail alerts module from prestashop. The problem is for me that when You leave the field for e-mail blank and click "notify me" it displays that e-mail address is invalid but doesn't give a chance to fix it untlit page is refreshed. How can i validate form that it won't let click person until good mail with [email protected] format is placed and people won't have to reload page after every error. 

We have it on Presta 1.7.6.1