on 2013-11-09
JavaScript - Event
-
event type 事件名稱
-
event target 事件發生在哪一個目標上
-
event handler or listener 處理或回應的 function, 即監聽或註冊事件
-
event object 與事件關聯的物件
-
event propagation 氣泡(bubble)現象
-
default actions 觸發事件時的預設行為, 有時必須取消該行為
GlobalEventHandlers
- HTML
<button id="btn">Click</button>
- JavaScript
var nodeBtn = document.getElementById('btn');
nodeBtn.onclick = function (e) {
alert('ok');
};
event
- HTML
<button id="btn">Click</button>
Use addEventListener(only IE9 up) addEventListener
- JavaScript
var nodeBtn = document.getElementById('btn');
nodeBtn.addEventListener('click', function () {
alert('ok');
});
delegate
If use dynamic page the dom maybe not init in the page load So use delegate
var div = document.createElement('div'),
prefix = ['moz','webkit','ms','o'].filter(function (prefix) {
return prefix + 'MatchesSelector' in div;
})[0] + 'MatchesSelector';
Element.prototype.addDelegateListener = function(type, selector, fn) {
this.addEventListener( type, function(e) {
var target = e.target;
while(target && target !== this && !target[prefix](selector)) {
target = target.parentNode;
}
if(target && target !== this) {
return fn.call(target, e);
}
}, false );
};
- example
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>javascript - delegate</title>
</head>
<body>
</body>
<script>
var div = document.createElement('div'),
prefix = ['moz','webkit','ms','o'].filter(function (prefix) {
return prefix + 'MatchesSelector' in div;
})[0] + 'MatchesSelector';
Element.prototype.addDelegateListener = function(type, selector, fn) {
this.addEventListener( type, function(e){
var target = e.target;
while(target && target !== this && !target[prefix](selector)) {
target = target.parentNode;
}
if(target && target !== this) {
return fn.call(target, e);
}
}, false );
};
document.querySelector('body').addDelegateListener('click', '#btn', function () {
alert('ok');
});
document.body.innerHTML = '<button id="btn">Click</button>';
</script>
</html>
Refer - addEventListener for new elements