Validate parentheses "()" and "[]" are balanced
A short review;


checkBalancedBrackets("([)]") returns true, not sure that was the intention
b1 and b2 are not great names, what does the b stand for?
Using arrays is not needed, all the code does is counting numbers, you can just use numbers
The inconsistent use of curly braces in your if and else if clauses is not good