test()var str = "cat";var reStr = /cat/;alert(reStr.test(str)); 输出为:true它的返回值为true or false ; exec()var str = "a bat , a Cat , a fat cat";var reStr = /at/; var arrMatch = reStr.exec(str); 输出为:at 它的返回值为第一次匹配; match()var str = "a bat , a Cat , a fat cat";var reStr = /at/; var arrMatch = str.match(reStr); 输出为:at var str = "a bat , a Cat , a fat cat";var reStr = /at/i;var arrMatch = str.match(reStr); 输出为:at var str = "a bat , a Cat , a fat cat";var reStr = /at/ig;var arrMatch = str.match(reStr); 输出为:at,at,at,at
它的返回值为所有的匹配,是一个数组