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你可能不需要jQuery!使用原生JavaScript 进行开发

你可能不需要jQuery!使用原生JavaScript 进行开发

很多的 JavaScript 开发人员,包括我在内,都很喜欢 jQuery。因为它的简单,因为它有很多丰富的插件可供使用,和其它优秀的工具一样,jQuery 让我们开发人员能够更轻松的开发网站和 Web 应用。
然而,另一方面,作为前端开发的基础框架,jQuery 包含大量的兼容性代码和扩展功能,其中有很多在你的整个项目中可能都不会用到。其实如果你只是针对现代浏览器,很多功能使用原生的 JavaScript 就可以实现,即使是拖后腿的低版本 IE 浏览器,兼容性也是很容易处理的。
下面就带大家一起看看在 IE 浏览器环境中如果使用原生 JavaScript 代码实现 jQuery 中的功能。如果你打算自己开发一个小的基础框架,可以好好参考一下这些代码的实现
Ajax Post

jQuery:

$.ajax({
type: ‘POST’,
url: ‘/my/url’,
data: data
});

IE8+:

var request = new XMLHttpRequest();
request.open(‘POST’, ‘/my/url’, true);
request.send(data);

Ajax Get
 jQuery:

$.ajax({
type: ‘GET’,
url: ‘/my/url’,
success: function(resp) {

},
error: function() {

}
});

IE8+:

request = new XMLHttpRequest();
request.open(‘GET’, ‘/my/url’, true);

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

request.send();
request = null;

加载 JSON
jQuery:

$.getJSON(‘/my/url’, function(data) {

});

IE8+:

request = new XMLHttpRequest();
request.open(‘GET’, ‘/my/url’, true);

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

request.send();
request = null;

淡入效果
jQuery:

$(el).fadeIn();

IE8+:

function fadeIn(el) {
var opacity = 0;

el.style.opacity = 0;
el.style.filter = ”;

var last = +new Date();
var tick = function() {
opacity += (new Date() – last) / 400;
el.style.opacity = opacity;
el.style.filter = ‘alpha(opacity=’ + (100 * opacity)|0 + ‘)';

last = +new Date();

if (opacity < 1) {
(window.requestAnimationFrame && requestAnimationFrame(tick)) || setTimeout(tick, 16);
}
};

tick();
}

fadeIn(el);

显示和隐藏
jQuery:

$(el).show();
$(el).hide();

IE8+:

el.style.display = ”;
el.style.display = ‘none';

添加 Class
jQuery:

$(el).addClass(className);

IE8+:

if (el.classList)
el.classList.add(className);
else
el.className += ‘ ‘ + className;

插入 HTML
jQuery:

$(el).before(htmlString);
$(parent).append(el);
$(el).after(htmlString);

IE8+:

el.insertAdjacentHTML(‘beforebegin’, htmlString);
parent.appendChild(el);
el.insertAdjacentHTML(‘afterend’, htmlString);

获取子节点
jQuery:

$(el).children();

IE8+:

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]);
}

循环节点
jQuery:

$(selector).each(function(i, el){

});

IE8+:

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){

});

清空节点
jQuery:

$(el).empty();

IE8+:

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

过滤节点
jQuery:

$(selector).filter(filterFn);

IE8+:

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);

查找元素
jQuery:

$(el).find(selector);
$(‘.my #awesome selector’);

IE8+:

el.querySelectorAll(selector);
document.querySelectorAll(‘.my #awesome selector’);

获取属性、HTML或者文本
jQuery:

$(el).attr(‘tabindex’);
$(el).html();
$(‘<div>’).append($(el).clone()).html();
$(el).text();

IE8+:

el.getAttribute(‘tabindex’);
el.innerHTML
el.outerHTML
el.textContent || el.innerText

判断是否包含某个 css class
jQuery:

$(el).hasClass(className);

IE8+:

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

选择器匹配
jQuery:

$(el).is(‘.my-class’);

IE8+:

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 {
var nodes = el.parentNode.querySelectorAll(selector);
for (var i = nodes.length; i–;)
if (nodes[i] === el) {
return true;
}
return false;
}

matches(el, ‘.my-class’);

前一个节点
jQuery:

$(el).prev();

IE8+:

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

el.previousElementSibling || previousElementSibling(el);

后一个节点
jQuery:

$(el).next();

IE8+:

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

el.nextElementSibling || nextElementSibling(el);

外部高度
jQuery:

$(el).outerHeight()

IE8+:

function outerHeight(el, includeMargin){
var height = el.offsetHeight;

if(includeMargin){
var style = el.currentStyle || getComputedStyle(el);
height += parseInt(style.marginTop) + parseInt(style.marginBottom);
}
return height;
}

outerHeight(el, true);

判断是否数组
jQuery:

$.isArray(arr);

IE8+:

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

isArray(arr);

数组转换
jQuery:

$.map(array, function(value, index){

})

IE8+:

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){

})

类似的还有很多很多,可以参考这里:http://youmightnotneedjquery.com/

时间:2014-02-24

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