devot:eeDevoted to ExpressionEngine

Hello, can anyone tell me how to validate email input only once?
I mean, if I set class=“require_email” instead of class=“require require_email” as shown in the example, the validation bypasses if the text is empty.
I would like just one error message with email input instead of “This field is required” and “Invalid email address”.
The class “require_email” should perform both required and valid email check at one time, is this possible?
I tried editing the regex for email with no luck.

Here is my code for email input.

The plugin is based on this jQuery plugin (https://github.com/posabsolute/jQuery-Validation-Engine)  Perhaps there is a hidden setting for this, but i cannot find it :-(