Example #1 Examples of valid patterns

• /<\/\w+>/
• |(\d{3})-\d+|Sm
• /^(?i)php[34]/
• {^\s+(\s+)?$}

Example #2 Examples of invalid patterns

• /href='(.*)' - missing ending delimiter
• /\w+\s*\w+/J - unknown modifier 'J'
• 1-\d3-\d3-\d4| - missing starting delimiter