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源代码：
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<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>素材8网教程(study.sucai8.cn)</title> </head> <body> <script> var str = "Is is the cost of of gasoline going up up"; var patt1 = /\b([a-z]+) \1\b/ig; document.write(str.match(patt1)); </script> </body> </html>
运行结果