PHP Level 1

$a = 10;

If ($this->isComplete()) echo "finished";

Printf('%d',10);

Document.writeln(requestObject.parameter("id"))

Echo $switch ? $switch : '';

Fib(5)

( $i > LAST_ITEM )

$n = 100;

5 + 10

Function total( $x, $y, $z ) { return $x + $y + $z; }

While (true) { echo "x"; }

F(10)

$a + $b

$n = array( 1, 3, 9, 27 );

Print "10 - 5 = 5";

MyClass::myMethod($x);

$obj->myMethod($x);

$obj.myMethod($x);

$n = new MyClass(10)->myMethod($x);

$obj->$funcName($parameter);

The POST variable name is wrong.

The input is not escaped and quoted before being inserted into the query.

The "Hello" message was quoted incorrectly, and won't display the arugment.

The input is not sanitized before printing to the browser.

An HTML tag is not closed.

For(....), if (....) { $a[] = ... }

Foreach(....) preg_match

Map( function () = '....' ); substr(); array_push();

Grep(); keys(); unshift()

Array(... select from( where(...) );

5

10

50

300

2000

Analyze your queries, and add indexes to tables to speed them up.

Add an object cache like APC or Zend.

Generate a static home page, and for some internal pages.

Move the database to it's own machine and connect to it via TCP/IP

Use memcached to store serialized query results, and use it as a result cache.

Function calls are expensive.

Function call stack can run out of space.

Consumes lots of memory.

Difficult to understand.

It's easier to use arrays and indices.

Case folding causes similarly named files to overwrite another.

Calling mail() fails.

Executing code that calls OLE fails.

File paths stop working.

Missing or not-ported extensions.