Increase value of a variable on LMS using by default Exit button of player

Hi All,

I have an assessment with by default Storyline player using Exit button, User is allowed to pass the assessment in three attempts and what i want if the user will exit the course in the first attempt and when he/she resumes the course the attempt variable count will increases. 

I tried through javascript and able to perform both the actions(Increased the value of variable and exit the course, checked via reference of variable) on by default button but when i resumes the course the value of the attempt was not saved on LMS, it was the same as before i left off.

Thanks