如何在没有内联 JavaScript 或外部库的情况下做到这一点
一般建议避免使用内联 JavaScript,但很少有如何做到这一点的示例。
这是我将事件附加到按钮的方式。
与简单的onClick 属性相比,推荐的方法要多长时间,我并不完全满意。
现代浏览器
- 在文档加载完成之前工作。
- 非常高效。
- 将 JS 与 HTML 分开。
- JS 在
<head>
const OnEvent = (doc) => {
return {
on: (type, selector, callback) => {
doc.addEventListener(type, (event)=>{
if(!event.target.matches(selector)) return;
callback.call(event.target, event);
}, false);
}
}
};
OnEvent(document).on('click', '.btn', function (e) {
let div = document.createElement("div");
div.innerHTML = "click " + e.target.id + "!";
document.body.appendChild(div);
});
<button id="b1" class="btn">Button 1</button>
<button id="b2" class="btn">Button 2</button>
<button id="b3">Do nothing</button>
仅限 2014 年浏览器
<button class="btn" id="b1">Button</button>
<script>
let OnEvent = (doc) => {
return {
on: (event, className, callback) => {
doc.addEventListener('click', (event)=>{
if(!event.target.classList.contains(className)) return;
callback.call(event.target, event);
}, false);
}
}
};
OnEvent(document).on('click', 'btn', function (e) {
window.console.log(this.id, e);
});
</script>
仅限 2013 年浏览器
<!DOCTYPE html>
<html>
<head>
<script>
(function(doc){
var hasClass = function(el,className) {
return el.classList.contains(className);
}
doc.addEventListener('click', function(e){
if(hasClass(e.target, 'click-me')){
e.preventDefault();
doSomething.call(e.target, e);
}
});
})(document);
function insertHTML(str){
var s = document.getElementsByTagName('script'), lastScript = s[s.length-1];
lastScript.insertAdjacentHTML("beforebegin", str);
}
function doSomething(event){
console.log(this.id); // this will be the clicked element
}
</script>
<!--... other head stuff ...-->
</head>
<body>
<!--Best if you inject the button element with javascript if you plan to support users with javascript disabled-->
<script>
insertHTML('<button class="click-me" id="btn1">Button 1</button>');
</script>
<!--Use this when you don't care about broken buttons when javascript is disabled.-->
<!--buttons can be used outside of forms https://stackoverflow.com/a/14461672/175071 -->
<button class="click-me" id="btn2">Button 2</button>
<input class="click-me" type="button" value="Button 3" id="btn3">
<!--Use this when you want to lead the user somewhere when javascript is disabled-->
<a class="click-me" href="/path/to/non-js/action" id="btn4">Button 4</a>
</body>
</html>
跨浏览器
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
(function(doc){
var cb_addEventListener = function(obj, evt, fnc) {
// W3C model
if (obj.addEventListener) {
obj.addEventListener(evt, fnc, false);
return true;
}
// Microsoft model
else if (obj.attachEvent) {
return obj.attachEvent('on' + evt, fnc);
}
// Browser don't support W3C or MSFT model, go on with traditional
else {
evt = 'on'+evt;
if(typeof obj[evt] === 'function'){
// Object already has a function on traditional
// Let's wrap it with our own function inside another function
fnc = (function(f1,f2){
return function(){
f1.apply(this,arguments);
f2.apply(this,arguments);
}
})(obj[evt], fnc);
}
obj[evt] = fnc;
return true;
}
return false;
};
var hasClass = function(el,className) {
return (' ' + el.className + ' ').indexOf(' ' + className + ' ') > -1;
}
cb_addEventListener(doc, 'click', function(e){
if(hasClass(e.target, 'click-me')){
e.preventDefault ? e.preventDefault() : e.returnValue = false;
doSomething.call(e.target, e);
}
});
})(document);
function insertHTML(str){
var s = document.getElementsByTagName('script'), lastScript = s[s.length-1];
lastScript.insertAdjacentHTML("beforebegin", str);
}
function doSomething(event){
console.log(this.id); // this will be the clicked element
}
</script>
<!--... other head stuff ...-->
</head>
<body>
<!--Best if you inject the button element with javascript if you plan to support users with javascript disabled-->
<script type="text/javascript">
insertHTML('<button class="click-me" id="btn1">Button 1</button>');
</script>
<!--Use this when you don't care about broken buttons when javascript is disabled.-->
<!--buttons can be used outside of forms https://stackoverflow.com/a/14461672/175071 -->
<button class="click-me" id="btn2">Button 2</button>
<input class="click-me" type="button" value="Button 3" id="btn3">
<!--Use this when you want to lead the user somewhere when javascript is disabled-->
<a class="click-me" href="/path/to/non-js/action" id="btn4">Button 4</a>
</body>
</html>
jQuery 跨浏览器
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
(function($){
$(document).on('click', '.click-me', function(e){
doSomething.call(this, e);
});
})(jQuery);
function insertHTML(str){
var s = document.getElementsByTagName('script'), lastScript = s[s.length-1];
lastScript.insertAdjacentHTML("beforebegin", str);
}
function doSomething(event){
console.log(this.id); // this will be the clicked element
}
</script>
<!--... other head stuff ...-->
</head>
<body>
<!--Best if you inject the button element with javascript if you plan to support users with javascript disabled-->
<script type="text/javascript">
insertHTML('<button class="click-me" id="btn1">Button 1</button>');
</script>
<!--Use this when you don't care about broken buttons when javascript is disabled.-->
<!--buttons can be used outside of forms https://stackoverflow.com/a/14461672/175071 -->
<button class="click-me" id="btn2">Button 2</button>
<input class="click-me" type="button" value="Button 3" id="btn3">
<!--Use this when you want to lead the user somewhere when javascript is disabled-->
<a class="click-me" href="/path/to/non-js/action" id="btn4">Button 4</a>
</body>
</html>
您可以在文档准备好之前运行它,单击按钮将起作用,因为我们将事件附加到文档。
这是jsfiddle
出于某种奇怪的原因,insertHTML 函数在其中不起作用,即使它在我所有的浏览器中都可以使用。
如果您不介意 drawbacks,您可以随时将 insertHTML 替换为 document.write
<script>
document.write('<button class="click-me" id="btn1">Button 1</button>');
</script>
来源: