OnlineCBT
1. PHP Syntax and Tag Structure
PHP code blocks are written inside the standard opening tag and closing tag ?>. If a file contains exclusively PHP code, it is recommended best practice to omit the closing tag ?> to prevent accidental whitespace or newlines from causing header errors.
if file contains only PHP code2. Semicolons and Statement Termination
Every PHP instruction or statement must terminate with a semicolon (;). Forgetting a semicolon is the most common cause of Parse Error: syntax error, unexpected token in PHP.
3. Comments in PHP
PHP supports single-line and multi-line comments for code documentation:
4. Output Mechanisms: echo vs print
Both echo and print are language constructs used to display output to the screen, but they have subtle distinctions:
| Feature | echo |
print |
|---|---|---|
| Return Value | Has no return value (void). | Always returns 1, allowing it to be used in expressions. |
| Arguments | Can take multiple parameters separated by commas. | Takes only one argument. |
| Performance | Marginally faster than print. | Slightly slower due to returning a value. |
";
echo "Parameter 1", ", ", "Parameter 2
";
// Using print
print "Printed with print statement
";
// Short echo tag inside HTML templates
// is equivalent to
$pageTitle = "Dashboard";
?>
5. Case Sensitivity Rules in PHP
- Variables are case-sensitive:
$color,$Color, and$COLORare three completely different variables. - Keywords, function names, and class names are case-insensitive:
echo,ECHO,if,IF,count(),COUNT()resolve to the same instruction. However, maintaining consistent lowercase syntax is the professional convention.
