JS格式化日期例子

  var str = '{y}-{m}-{d}';
  var reg = /{(y|m|d)+}/g;
  var obj = {
    y: 2018,
    m: 9,
    d: 26
  }
  str = str.replace(reg, function($1, $2, $3) {
    return obj[$2]
  });