或许你并不需要jQuery

var request = new XMLHttpRequest();
request.open('GET', '/my/url', true);

request.onreadystatechange = function () {
  if (this.readyState === 4) {
    if (this.status >= 200 && this.status < 400) {
      // Success!
      var data = JSON.parse(this.responseText);
    } else {
      // Error :(
    }
  }
};

request.send();
request = null;

var request = new XMLHttpRequest();
request.open('GET', '/my/url', true);

request.onload = function () {
  if (request.status >= 200 && request.status < 400) {
    // Success!
    var data = JSON.parse(request.responseText);
  } else {
    // We reached our target server, but it returned an error
  }
};

request.onerror = function () {
  // There was a connection error of some sort
};

request.send();

var request = new XMLHttpRequest();
request.open('GET', '/my/url', true);

request.onload = function () {
  if (this.status >= 200 && this.status < 400) {
    // Success!
    var data = JSON.parse(this.response);
  } else {
    // We reached our target server, but it returned an error
  }
};

request.onerror = function () {
  // There was a connection error of some sort
};

request.send();

function load(selector, path) {
  var request = new XMLHttpRequest();
  request.open('GET', path, true);
  request.onreadystatechange = function () {
    if (this.readyState === 4) {
      if (this.status >= 200 && this.status < 400) {
        // Success!
        var elements = document.querySelector(selector);
        for (var i = 0; i < elements.length; i++) {
          elements[i].innerHTML = this.responseText;
        }
      } else {
        // Error :(
      }
    }
  };
}

load('#some.selector', '/path/to/template.html');

var request = new XMLHttpRequest();
request.open('POST', '/my/url', true);
request.setRequestHeader(
  'Content-Type',
  'application/x-www-form-urlencoded; charset=UTF-8'
);
request.send(data);

function request(success, error) {
  var request = new XMLHttpRequest();
  request.open('GET', '/my/url', true);

  request.onreadystatechange = function () {
    if (this.readyState === 4) {
      if (this.status >= 200 && this.status < 400) {
        // Success! If you expect this to be JSON, use JSON.parse!
        success(this.responseText, this.status);
      } else {
        error();
      }
    }
  };

  request.send();
}

function request(success, error) {
  var request = new XMLHttpRequest();
  request.open('GET', '/my/url', true);

  request.onload = function () {
    if (this.status >= 200 && this.status < 400) {
      // Success! If you expect this to be JSON, use JSON.parse!
      success(this.responseText, this.status);
    } else {
      // We reached our target server, but it returned an error
      error();
    }
  };

  request.onerror = function () {
    error();
  };

  request.send();
}

if (el.classList) {
  el.classList.add(className);
} else {
  var current = el.className,
    found = false;
  var all = current.split(' ');
  for (var i = 0; i < all.length, !found; i++) found = all[i] === className;
  if (!found) {
    if (current === '') el.className = className;
    else el.className += ' ' + className;
  }
}

el.classList.add(className);

target.insertAdjacentElement('afterend', element);

parent.appendChild(el);

parent.appendChild(el);

target.insertAdjacentElement('beforebegin', element);

var children = [];
for (var i = el.children.length; i--; ) {
  // Skip comment nodes on IE8
  if (el.children[i].nodeType != 8) children.unshift(el.children[i]);
}

el.children;

el.cloneNode(true);

function closest(el, sel) {
  Element.prototype.matches ||
    (Element.prototype.matches =
      Element.prototype.matchesSelector ||
      Element.prototype.mozMatchesSelector ||
      Element.prototype.msMatchesSelector ||
      Element.prototype.oMatchesSelector ||
      Element.prototype.webkitMatchesSelector ||
      function (b) {
        b = (this.document || this.ownerDocument).querySelectorAll(b);
        for (var a = b.length; 0 <= --a && b.item(a) !== this; );
        return -1 < a;
      });
  Element.prototype.closest ||
    (Element.prototype.closest = function (b) {
      var a = this;
      do {
        if (a.matches(b)) return a;
        a = a.parentElement || a.parentNode;
      } while (null !== a && 1 === a.nodeType);
      return null;
    });
  return el.closest(sel);
}

closest(el, sel);

function closest(el, sel) {
  Element.prototype.matches ||
    (Element.prototype.matches =
      Element.prototype.msMatchesSelector ||
      Element.prototype.webkitMatchesSelector);
  Element.prototype.closest ||
    (Element.prototype.closest = function (c) {
      var a = this;
      do {
        if (a.matches(c)) return a;
        a = a.parentElement || a.parentNode;
      } while (null !== a && 1 === a.nodeType);
      return null;
    });
  return el.closest(sel);
}

closest(el, sel);

el.closest(sel);

el !== child && el.contains(child);

!!el.querySelector(selector);

function generateElements(html) {
  var div = document.createElement('div');
  div.innerHTML = html;
  if (div.children.length === 0) {
    return null;
  }
  if (div.children.length === 1) {
    return div.firstChild;
  } else {
    return div.children;
  }
}

generateElements('<div>Hello World!</div>');

function forEachElement(selector, fn) {
  var elements = document.querySelectorAll(selector);
  for (var i = 0; i < elements.length; i++) fn(elements[i], i);
}

forEachElement(selector, function (el, i) {});

var elements = document.querySelectorAll(selector);
Array.prototype.forEach.call(elements, function (el, i) {});

while (el.firstChild) el.removeChild(el.firstChild);

function filter(selector, filterFn) {
  var elements = document.querySelectorAll(selector);
  var out = [];
  for (var i = elements.length; i--; ) {
    if (filterFn(elements[i])) out.unshift(elements[i]);
  }
  return out;
}

filter(selector, filterFn);

Array.prototype.filter.call(document.querySelectorAll(selector), filterFn);

el.querySelectorAll(selector);

document.querySelectorAll('.my #awesome selector');

document.querySelectorAll(el)[0];

el.getAttribute('tabindex');

function getHeight(el) {
  var d = /^\d+(px)?$/i;
  if (window.getComputedStyle)
    el = parseFloat(getComputedStyle(el, null).height.replace('px', ''));
  else {
    var c = el.currentStyle.height;
    if (d.test(c)) el = parseInt(c);
    else {
      d = el.style.left;
      var e = el.runtimeStyle.left;
      el.runtimeStyle.left = el.currentStyle.left;
      el.style.left = c || 0;
      c = el.style.pixelLeft;
      el.style.left = d;
      el.runtimeStyle.left = e;
      el = c;
    }
  }
  return el;
}

getHeight(el);

parseFloat(getComputedStyle(el, null).height.replace('px', ''));

el.innerHTML;

el.outerHTML;

// Varies based on the properties being retrieved, some can be retrieved from el.currentStyle
// https://github.com/jonathantneal/Polyfills-for-IE8/blob/master/getComputedStyle.js

getComputedStyle(el)[ruleName];

el.textContent || el.innerText;

el.textContent;

function getWidth(el) {
  var d = /^\d+(px)?$/i;
  if (window.getComputedStyle)
    el = parseFloat(getComputedStyle(el, null).width.replace('px', ''));
  else {
    var c = el.currentStyle.width;
    if (d.test(c)) el = parseInt(c);
    else {
      d = el.style.left;
      var e = el.runtimeStyle.left;
      el.runtimeStyle.left = el.currentStyle.left;
      el.style.left = c || 0;
      c = el.style.pixelLeft;
      el.style.left = d;
      el.runtimeStyle.left = e;
      el = c;
    }
  }
  return el;
}

getWidth(el);

parseFloat(getComputedStyle(el, null).width.replace('px', ''));

if (el.classList) el.classList.contains(className);
else new RegExp('(^| )' + className + '( |$)', 'gi').test(el.className);

el.classList.contains(className);

function index(el) {
  if (!el) return -1;
  var i = 0;
  while (el) {
    el = el.previousSibling;
    if (el && el.nodeType === 1) i++;
  }
  return i;
}

function index(el) {
  if (!el) return -1;
  var i = 0;
  while ((el = el.previousElementSibling)) {
    i++;
  }
  return i;
}

var els = document.querySelectorAll(el);
els[els.length - 1];

el === otherEl;

var matches = function (el, selector) {
  var _matches =
    el.matches ||
    el.matchesSelector ||
    el.msMatchesSelector ||
    el.mozMatchesSelector ||
    el.webkitMatchesSelector ||
    el.oMatchesSelector;

  if (_matches) {
    return _matches.call(el, selector);
  } else {
    if (el.parentNode === null) return false;
    var nodes = el.parentNode.querySelectorAll(selector);
    for (var i = nodes.length; i--; ) {
      if (nodes[i] === el) return true;
    }
    return false;
  }
};

matches(el, '.my-class');

var matches = function (el, selector) {
  return (
    el.matches ||
    el.matchesSelector ||
    el.msMatchesSelector ||
    el.mozMatchesSelector ||
    el.webkitMatchesSelector ||
    el.oMatchesSelector
  ).call(el, selector);
};

matches(el, '.my-class');

// nextSibling can include text nodes
function nextElementSibling(el) {
  do {
    el = el.nextSibling;
  } while (el && el.nodeType !== 1);
  return el;
}

el.nextElementSibling || nextElementSibling(el);

el.nextElementSibling;

var rect = el.getBoundingClientRect();

{
  top: rect.top + document.body.scrollTop,
  left: rect.left + document.body.scrollLeft,
};

function offset(el) {
  box = el.getBoundingClientRect();
  docElem = document.documentElement;
  return {
    top: box.top + window.pageYOffset - docElem.clientTop,
    left: box.left + window.pageXOffset - docElem.clientLeft,
  };
}

el.offsetParent || el;

el.offsetHeight;

function outerHeight(el) {
  var height = el.offsetHeight;
  var style = el.currentStyle || getComputedStyle(el);

  height += parseInt(style.marginTop) + parseInt(style.marginBottom);
  return height;
}

outerHeight(el);

function outerHeight(el) {
  var height = el.offsetHeight;
  var style = getComputedStyle(el);

  height += parseInt(style.marginTop) + parseInt(style.marginBottom);
  return height;
}

outerHeight(el);

el.offsetWidth;

function outerWidth(el) {
  var width = el.offsetWidth;
  var style = el.currentStyle || getComputedStyle(el);

  width += parseInt(style.marginLeft) + parseInt(style.marginRight);
  return width;
}

outerWidth(el);

function outerWidth(el) {
  var width = el.offsetWidth;
  var style = getComputedStyle(el);

  width += parseInt(style.marginLeft) + parseInt(style.marginRight);
  return width;
}

outerWidth(el);

el.parentNode;

function offset(el) {
  box = el.getBoundingClientRect();
  docElem = document.documentElement;
  return {
    top: box.top + (window.pageYOffset || docElem.scrollTop),
    left: box.left + (window.pageXOffset || docElem.scrollLeft),
  };
}

el.getBoundingClientRect();

parent.insertBefore(el, parent.firstChild);

// prevSibling can include text nodes
function previousElementSibling(el) {
  do {
    el = el.previousSibling;
  } while (el && el.nodeType !== 1);
  return el;
}

el.previousElementSibling || previousElementSibling(el);

el.previousElementSibling;

if (el.parentNode !== null) {
  el.parentNode.removeChild(el);
}

el.removeAttribute('tabindex');

function removeClass(el, className) {
  var classes = className.split(' ');
  for (var i = 0; i < classes.length; i++) {
    if (el.classList) {
      el.classList.remove(classes[i]);
    } else {
      el.className = el.className
        .replace(new RegExp('(?:^|\\s)' + classes[i] + '(?:\\s|$)'), ' ')
        .replace(new RegExp(/^\s+|\s+$/g), '');
    }
  }
}

el.classList.remove(className);

el.outerHTML = string;

el.setAttribute('tabindex', 3);

function setHeight(el, val) {
  if (typeof val === 'function') val = val();
  if (typeof val === 'string') el.style.height = val;
  else el.style.height = val + 'px';
}

setHeight(el, val);

el.innerHTML = string;

// Use a class if possible
el.style.borderWidth = '20px';

if (el.textContent !== undefined) el.textContent = string;
else el.innerText = string;

el.textContent = string;

function setWidth(el, val) {
  if (typeof val === 'function') val = val();
  if (typeof val === 'string') el.style.width = val;
  else el.style.width = val + 'px';
}

setWidth(el, val);

var siblings = function (el) {
  if (el.parentNode === null) return [];

  var siblingElements = Array.prototype.slice.call(el.parentNode.children);

  for (var i = siblingElements.length; i--; ) {
    if (siblingElements[i] === el) {
      return siblingElements.splice(i, 1);
    }
  }

  return siblingElements;
};

siblings(el);

var siblings = function (el) {
  if (el.parentNode === null) return [];

  return Array.prototype.filter.call(el.parentNode.children, function (child) {
    return child !== el;
  });
};

siblings(el);

if (el.classList) {
  el.classList.toggle(className);
} else {
  var classes = el.className.split(' ');
  var existingIndex = -1;
  for (var i = classes.length; i--; ) {
    if (classes[i] === className) existingIndex = i;
  }

  if (existingIndex >= 0) classes.splice(existingIndex, 1);
  else classes.push(className);

  el.className = classes.join(' ');
}

if (el.classList) {
  el.classList.toggle(className);
} else {
  var classes = el.className.split(' ');
  var existingIndex = classes.indexOf(className);

  if (existingIndex >= 0) classes.splice(existingIndex, 1);
  else classes.push(className);

  el.className = classes.join(' ');
}

el.classList.toggle(className);

function forEach(array, fn) {
  for (var i = 0; i < array.length; i++) fn(array[i], i);
}

forEach(array, function (item, i) {});

array.forEach(function (item, i) {});

fn.apply(context, arguments);

fn.bind(context);

var deepExtend = function (out) {
  out = out || {};

  for (var i = 1; i < arguments.length; i++) {
    var obj = arguments[i];

    if (!obj) continue;

    for (var key in obj) {
      if (obj.hasOwnProperty(key)) {
        if (typeof obj[key] === 'object' && obj[key] !== null) {
          if (obj[key] instanceof Array) out[key] = obj[key].slice(0);
          else out[key] = deepExtend(out[key], obj[key]);
        } else out[key] = obj[key];
      }
    }
  }

  return out;
};

deepExtend({}, objA, objB);

var extend = function (out) {
  out = out || {};

  for (var i = 1; i < arguments.length; i++) {
    if (!arguments[i]) continue;

    for (var key in arguments[i]) {
      if (arguments[i].hasOwnProperty(key)) out[key] = arguments[i][key];
    }
  }

  return out;
};

extend({}, objA, objB);

function indexOf(array, item) {
  for (var i = 0; i < array.length; i++) {
    if (array[i] === item) return i;
  }
  return -1;
}

indexOf(array, item);

array.indexOf(item);

isArray =
  Array.isArray ||
  function (arr) {
    return Object.prototype.toString.call(arr) == '[object Array]';
  };

isArray(arr);

Array.isArray(arr);

function isNumeric(num) {
  if (typeof num === 'number') return num - num === 0;
  if (typeof num === 'string' && num.trim() !== '')
    return Number.isFinite ? Number.isFinite(+num) : isFinite(+num);
  return false;
}

isNumeric(val);

function map(arr, fn) {
  var results = [];
  for (var i = 0; i < arr.length; i++) results.push(fn(arr[i], i));
  return results;
}

map(array, function (value, index) {});

array.map(function (value, index) {});

new Date().getTime();

Date.now();

function objectEach(obj, callback) {
  for (var key in obj) {
    if (Object.prototype.hasOwnProperty.call(obj, key)) {
      callback(key, obj[key]);
    }
  }
}

objectEach(obj, function (key, value) {});

var parseHTML = function (str) {
  var el = document.createElement('div');
  el.innerHTML = str;
  return el.childNodes;
};

parseHTML(htmlString);

var parseHTML = function (str) {
  var tmp = document.implementation.createHTMLDocument('');
  tmp.body.innerHTML = str;
  return Array.prototype.slice.call(tmp.body.childNodes);
};

parseHTML(htmlString);

JSON.parse(string);

function slice(els, start, end) {
  var f = Array.prototype.slice;
  try {
    f.call(document.documentElement);
  } catch (h) {
    Array.prototype.slice = function (g, b) {
      b = 'undefined' !== typeof b ? b : this.length;
      if ('[object Array]' === Object.prototype.toString.call(this))
        return f.call(this, g, b);
      var e = [];
      var a = this.length;
      var c = g || 0;
      c = 0 <= c ? c : Math.max(0, a + c);
      var d = 'number' == typeof b ? Math.min(b, a) : a;
      0 > b && (d = a + b);
      d -= c;
      if (0 < d)
        if (((e = Array(d)), this.charAt))
          for (a = 0; a < d; a++) e[a] = this.charAt(c + a);
        else for (a = 0; a < d; a++) e[a] = this[c + a];
      return e;
    };
  }
  return els.slice(start, end);
}

slice(els, start, end);

els.slice(begin, end);

function toArray(selector) {
  var array = [];
  var elements = document.querySelectorAll(selector);
  for (var i = 0; i < elements.length; i++) array.push(elements[i]);
  return array;
}

string.replace(/^\s+|\s+$/g, '');

string.trim();

Object.prototype.toString
  .call(obj)
  .replace(/^\[object (.+)\]$/, '$1')
  .toLowerCase();