JS正则表达式中的attributes为"m"
2015-03-12 23:33
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<span style="font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">今天在做项目是写了这么一段JS代码:</span>
var str1 = "12345"; var str2 = "24536"; var regex = /^[1-9][0-9]{0,}$/g; alert(regex.test(str1));//true alert(regex.test(str2));//false
为什么会出现上面regex.test(str2)为false呢,其实这里要讲到我们所设置的attributes为g,也就是全局,不是支持多行匹配的,故只能进行单行匹配,第一次匹配成功为true,第二次匹配是不支持故为false,如果我们设置的正则表达式想使用多次的话,那么就要设置"m"的属性。
var regex = <span style="font-family: Arial, Helvetica, sans-serif;">/^[1-9][0-9]{0,}$/m;</span>
<span style="font-family: Arial, Helvetica, sans-serif;"></span><pre name="code" class="javascript">var str1 = "123456"; var str2 = "234342"; alert(regex.test(str1));//true alert(regex.test(str2));//true
<span style="font-family: Arial, Helvetica, sans-serif;">1.声明正则表达式的两种方式</span>
<ol><li><span style="font-family: Arial, Helvetica, sans-serif;">/pattern/attributes</span></li><li><span style="font-family: Arial, Helvetica, sans-serif;">new RegExp('pattern','attributes');</span></li></ol><span style="font-family: Arial, Helvetica, sans-serif;"> 2. 使用正则表达式的三种方法</span>
<span style="font-family: Arial, Helvetica, sans-serif;"> test: 用法regex.test(str1);//查找str1中第一个匹配正则表达式的字符串,匹配返回true,否则返回false;</span>
<span style="font-family: Arial, Helvetica, sans-serif;"> 略。。。。。。。</span>
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