使用javascript将时间转换成今天，昨天，前天等格式

function transDate() {
    var $time =document.getElementById("share-time");
    var date = $time.innerHTML.trim();
    var tt = new Date(parseInt(date));
    var days = parseInt((new Date().getTime() - date) / 86400000);
    var today = new Date().getDate();
    var year = tt.getFullYear();
    var mouth = tt.getMonth() + 1;
    var day = tt.getDate();
    var time = tt.getHours() < 10 ? "0" + tt.getHours() : tt.getHours();
    var min = tt.getMinutes() < 10 ? "0" + tt.getMinutes() : tt.getMinutes();
    var result, offset;
　　　　　　　offset = Math.abs(today - day);
　　　　if (days < 4&&offset<4) {
　　　　　　　if (offset === 0) {
        result = "今天" + time + ":" + min;
      } else if (offset === 1) {
        result = "昨天" + time + ":" + min;
      } else if (offset === 2) {
        result = "前天" + time + ":" + min;
      }
    } else {
      result = year + "-" + mouth + "-" + day + " " + time + ":" + min;
    }
    $time.innerHTML = result;
  }
  transDate();