js学员，有个作业问问大家

Question

求解答。谢谢

Answer 1

 1
    var str = "23fadfdf93d8fdgf345";
    var arr = str.match(/[a-z]+/gi);
    alert(arr.join('\n'))
2

    var str = "jfdjjdFDG3438ffgd#87613FGaghh";
    var kv = {}
    for (var i = 0; i < str.length; i++) { var c = str.charAt(i); kv[c] = (kv[c] || 0) + 1;}
    var arr = [],i=0;
    for (var k in kv) arr[i++] = { k: k, v: kv[k] }
    arr.sort(function (a, b) { return b.v - a.v });
    var maxV = arr[0].v;
    alert('出现次数最多字符如下')
    for (var i = 0; i < arr.length; i++) {
        if (arr[i].v == maxV) alert(arr[i].k + ':' + arr[i].v)
        else break;
    }
3
    var str = "http://www.baidu.com?name=lhl&id=1&passowrd=123456&sex=1&age=15";
    var queryString = str.split('?')[1]; 
    var kv = {},reg=/([^=&]+)=([^=&]+)/gi
    while (m = reg.exec(queryString)) kv[m[1]] = (kv[m[1]] ? kv[m[1]] + ',' : '') + m[2];
    alert(JSON.stringify(kv))