如何重写使用XHR和FormData向后兼容的JS?

编辑: 您可以覆盖 FormData 要创建这样的编码后字符串…

function FormData() {
  var obj = {}
  this.append = function(key, val) {
    obj[key] = val;
  }
  this.toString = function() {
    var s = "";
    for(var k in obj) {
      s += ((s.length == 0) ? "?" : "&");
      s += k;
      s += "=";
      s += encodeURIComponent(obj[k]);  // might want to use escape() instead
    }
    return s;
  }
}