- Mismatched punctuation. Any open quote mark, parenthesis, or curly bracket must have a corresponding closing quote mark, parenthesis, or curly bracket. Missing punctuation will create problems.
- Improper conditional expressions. Conditional expressions must be enclosed in parentheses. CORRECT: if (var1 == var2) INCORRECT: if var1 == var2. Comparison operators are different than assignment operators. CORRECT: if (var1 == var2) INCORRECT: if (var1 = var2).