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Example #1 �Ϸ�ģʽʾ��

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

Example #2 �Ƿ�ģʽʾ��

• /href='(.*)' - ȱʧ�����ָ���
• /\w+\s*\w+/J - δ֪ģʽ���η�"J"
• 1-\d3-\d3-\d4| - ȱʧ��ʼ�ָ���