exec方法为正则表达式匹配的文本搜索字符串。如果找到匹配，则返回结果数组; 否则，返回null。
语法
RegExpObject.exec( string );
下面是参数的详细信息：
返回值:
例子：
<html>
<head>
<title>JavaScript RegExp exec Method</title>
</head>
<body>
<script type="text/javascript">
var str = "Javascript is an interesting scripting language";
var re = new RegExp( "script", "g" );
var result = re.exec(str);
document.write("Test 1 - returned value : " + result);
re = new RegExp( "pushing", "g" );
var result = re.exec(str);
document.write("<br />Test 2 - returned value : " + result);
</script>
</body>
</html>
这将产生以下结果：
Test 1 - returned value : script Test 2 - returned value : null
