如何实时获取鼠标的当前坐标
本文来做一个简单的实时获取鼠标坐标的功能，在canvas动画开发中，获取鼠标的坐标，键盘的按键等等，都是常用的操作，我们就慢慢得把他们封装成一个公共库。
一、事件的兼容：
function bindEvent(obj, event, fn) {
if (obj.attachEvent) { //ie
obj.attachEvent('on' + event, function () {
fn.call(obj);
});
} else {
//chrome&ff
obj.addEventListener(event, fn, false);
}
}
上面兼容ie8以及修正this关键字在ie低版本的指向，下面兼容chrome和ff。其他更常用的封装可以参考我的javascript开源框架gdom
二、用立即表达式搭建一个基本的库
添加获取鼠标坐标的方法
;(function (window) {
window.G = {};
function bindEvent(obj, event, fn) {
if (obj.attachEvent) { //ie
obj.attachEvent('on' + event, function () {
fn.call(obj);
});
} else {
//chrome&ff
obj.addEventListener(event, fn, false);
}
}
G.getPos = function( dom ){
var oPos = { x : 0, y : 0 };
bindEvent( dom, 'mousemove', function( ev ){
var oEvent = ev || event, x, y;
if ( oEvent.pageX || oEvent.pageY ){
x = oEvent.pageX;
y = oEvent.pageY;
}else {
x = oEvent.clientX + document.body.scrollLeft || document.documentElement.scrollLeft;
y = oEvent.clientX + document.body.scrollTop || document.documentElement.scrollTop;
}
x -= dom.offsetLeft;
y -= dom.offsetTop;
oPos.x = x;
oPos.y = y;
} );
return oPos;
};
})(window);
三、引入封装的js库，绑定canvas为监听对象，打印当前鼠标的坐标
鼠标的坐标，我这里画了2根线，便于观察.
<head>
<meta charset='utf-8' />
<script>
;(function (window) {
window.G = {};
function bindEvent(obj, event, fn) {
if (obj.attachEvent) { //ie
obj.attachEvent('on' + event, function () {
fn.call(obj);
});
} else {
//chrome&ff
obj.addEventListener(event, fn, false);
}
}
G.getPos = function( dom ){
var oPos = { x : 0, y : 0 };
bindEvent( dom, 'mousemove', function( ev ){
var oEvent = ev || event, x, y;
if ( oEvent.pageX || oEvent.pageY ){
x = oEvent.pageX;
y = oEvent.pageY;
}else {
x = oEvent.clientX + document.body.scrollLeft || document.documentElement.scrollLeft;
y = oEvent.clientX + document.body.scrollTop || document.documentElement.scrollTop;
}
x -= dom.offsetLeft;
y -= dom.offsetTop;
oPos.x = x;
oPos.y = y;
} );
return oPos;
};
})(window);
</script>
<style>
#canvas{
border:1px dashed #aaa;
}
</style>
<script>
window.onload = function(){
var oCanvas = document.querySelector( "#canvas" ),
oGc = oCanvas.getContext( '2d' ),
width = oCanvas.width, height = oCanvas.height,
oInfo = document.querySelector( "#info" ),
oPos = G.getPos( oCanvas );
oCanvas.addEventListener( "mousemove", function(){
oGc.clearRect( 0, 0, width, height );
oGc.beginPath();
oGc.moveTo( oPos.x, 0 );
oGc.lineTo( oPos.x, height );
oGc.moveTo( 0, oPos.y );
oGc.lineTo( width, oPos.y );
oGc.closePath();
oGc.strokeStyle = '#09f';
oGc.stroke();
oInfo.innerHTML = '鼠标的当前坐标是:(' + oPos.x + ',' + oPos.y + ')';
}, false );
}
</script>
</head>
<body>
<canvas id="canvas" width="500" height="400"></canvas>
<p id="info"></p>
</body>
以上就是如何实时获取鼠标的当前坐标 的详细内容，更多请关注其它相关文章！
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