SOURCE

function indexs (str,str1){
    var arr = [];
var index = str.indexOf(str1);
while (index != -1){
    arr.push(index);
    index = str.indexOf(str1,index + 1);
}

console.log(arr);
console.log(arr.length);
}

indexs('abcoefoxyozzopp','o');
indexs(['red','blue','red','green','pink','red'],'red');

var str2 = 'abcoefoxyozzopp';
while (str2.indexOf('o') !== -1){
    str2 = str2.replace('o','*');
}
console.log(str2);

var str3 = 'byny,jtt,slzj';
console.log(str3.split(','));
var str4 = 'byny&jtt&slzj';
console.log(str4.split('&'));
var str5 = 'jtt';
var str6 = str5.toUpperCase();
console.log(str5);
console.log(str6);

//作业
var str7 = 'abaasdffggghhjjkkgfddsssss3444343';
console.log(str7.length);//字符串长度
console.log(str7[9]);//指定位置的字符
console.log(str7[0]);//指定位置的字符
console.log(str7[3]);//指定位置的字符
console.log(str7[5]);//指定位置的字符

//判断是否存在
function panduan(str8){
      if (str7.indexOf(str8) != -1){
    console.log('存在该字符')
}else {
    console.log('不存在该字符')
}
}
panduan('i');
panduan('c');
panduan('b');

//替换字符
function tihuan(str9,str10){
    while(str7.indexOf(str9) != -1){
       str7 = str7.replace(str9,str10);
    }
    return str7;
}

console.log(tihuan('g','22'));
console.log(tihuan('ss','b'));

//截取字符
console.log(str7.substr(1,5));

//最多字符和出现次数
var str11 = 'abaa4444gggsdffggghhjjkkgfddsssss3444343';
var ob = {};
for (i=0;i<str11.length;i++){
    var chars = str11.charAt(i);
    if (ob[chars]){
        ob[chars]++;
    }else{
        ob[chars]=1;
    }
}
var max = 0;
var ch = '';
for ( k in ob){
    if (ob[k]>max){
        max = ob[k];
        ch = k;
    }
}

console.log(max)
console.log(ch)

<div id="time">2019-9-9</div>
<script> var timer = document.getElementById('time');
console.log(timer);
console.dir(timer);
</script>