split.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
  <script>
      var arrStr=['st ig ood shit gonging good shit gonging good' ,'play admin office friend,quick ready thank yellow'];
      arrStr = arrStr.map(item=>{
          var  itemArrStr = item.split(' ');
          let length = 0;
          let str = ''
          for(let index=0;index<itemArrStr.length;index++){
              length+=itemArrStr[index].length+1;
              if(length>15){
                 length=0;
                 str +='<br/>'+itemArrStr[index]+' ';
              }else{
                  str +=itemArrStr[index]+' ';
              }

          }
          length=length-1;
          console.log(length);
          console.log(str);
          return str

      })

console.log('st ig ood shit'.length)
      console.log(arrStr)
  </script>
</body>
</html>