JS——三个运用正则的方法

trim()、replace()、search()

<script>
    //trim();去除前后的空格
    var str = "     你好  我很好！     ";
    console.log(str);
    console.log(str.trim());
    console.log("--------------------");

    //replace(); 替换和全局替换值。
    var str = "Today is fine day,today is fine day!"
    console.log(str);
    console.log(str.replace(/today/ig, "tomorrow"));//i忽略大小写，g代表全局
    console.log("--------------------");

    //search();  给字符差索引
    var str = "abcdefg";
    console.log(str.search(/bc/));
    console.log(str.indexOf("bc"));
</script>

trim()IE678的兼容写法

<script>
    var str = "     你好，我      很好！      ";
    console.log(str);
    console.log(trim(str));
    function trim(str) {
        var aaa = str.replace(/(^s+)|(s+$)/g, "");
        return aaa;
    }
</script>