If You Ever Wanted to Know How JavaScript Conditional Operators Executes
A basic conditional operators && OR || execution demo in JavaScript:
- Using the || operator (OR) 
 if (confirm('Do you agree, or...') || confirm('...do you wish to revert?')) { alert('As you wish...'); }
 
 If you click OK for first confirm() you will not see the second confirm(). When you use the || operator all conditions are checked until one is true.
 
 
 
- Using the && operator (AND) 
 if (confirm('Do you agree, and...') && confirm('...do you really confirm to agree?')) { alert('As you wish...'); }
 
 
 
 Even If you click OK for first confirm() you will still see second confirm(). When you use the && operator all conditions are checked and all must be true.