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JS提供三個截取字符串的方法,分別是:slice(),substring()和substr(),它們都可以接受一個或兩個參數:
var stmp = "rcinn.cn";
使用一個參數
alert(stmp.slice(3));//從第4個字符開始,截取到最後個字符;返回"nn.cn"
alert(stmp.substring(3));//從第4個字符開始,截取到最後個字符;返回"nn.cn"
使用兩個參數
alert(stmp.slice(1,5))//從第2個字符開始，到第5個字符；返回"cinn"
alert(stmp.substring(1,5));//從第2個字符開始，到第5個字符；返回"cinn"
如果只用一個參數並且為0的話，那麼返回整個參數
alert(stmp.slice(0));//返回整個字符串
alert(stmp.substring(0));//返回整個字符串
返回第一個字符
alert(stmp.slice(0,1));//返回"r"
alert(stmp.substring(0,1));//返回"r"
//在上面的例子中我們可以看出slice()和substring()的用法是相同的，返回的值也是一樣的，但當參數為負數時，他們的返回值卻不一樣，看下面的例子
alert(stmp.slice(2,-5));//返回"i"
alert(stmp.substring(2,-5));//返回"rc"
//從上面兩個例子可以看出slice(2,-5)實際上是slice(2,3)，負5加上字符串長度8轉換成正3(若第一位數字等於或大於第二位數字(slice()注意：這裏第二位數字如果是負數是加完字符串長度後的數字，而不是顯示的數字例：length=11,(7,-6),-6+11=5第二位小於第一位),則返回空字符串);而substring(2,-5)實際上是substring(2,0),負數轉換為0,substring總是把較小的數作為起始位置。
alert(stmp.substring(1,5))//從第2個字符開始，到第5個字符；返回"cinn"
alert(stmp.substr(1,5));//從第2個字符開始，截取5個字符；返回"cinn."
var phone = 15989012100;
phone.slice(-6) 取倒數後6位(第二個參數不用寫0)，return ‘012100 '；
phone.slice(-6，-4) 取倒數後4位到倒數6位，（-6+11，-4+11）=（5,7）；
// 日期比較大小 當日期每個月都小1時var nowdate = new Date();item = 2016-7-16;temp = item.split('-');if (temp[0] != curYear || temp[1] != curMonth) { return;}temp[1] = parseInt(temp[1]) + 1;date = new Date(temp.join('-'));if(date>=nowdate){執行A；}else{執行B；}替換指定字符串後的字母
var abc = 'adadada=ss';var j = abc.substring(abc.indexOf('=')+1,abc.length);var dsd =abc.replace(j,'haha'); --> dsd = 'adadada=haha'以上所述是小編給大家介紹的JS截取字符串的三種方法，希望對大家有所幫助。在此也非常感謝大家對好二三四網站的支持！
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