<!DOCTYPE html>
<html>
<head>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8" />
	<title>HTML5跑动的小人</title>
	<script charset="UTF-8" id="LA_COLLECT" src="//sdk.51.la/js-sdk-pro.min.js"></script>
<script>LA.init({id:"3I5bIv8SmL9oiD3Z",ck:"3I5bIv8SmL9oiD3Z"})</script>
</head>
<body>
<div align="center">
<canvas id="demo" style="border:1px solid #ddd;">您的浏览器不支持canvas标签,推荐您更换谷歌游览器，全面兼容html5。</canvas>
<script  type="text/javascript">
/**
 * Basic event handling object
 * @type {Object}
 * @date 2012-03-15
 * @author Eyson
 */
var eventjs = {
	//添加事件
	bind: function(elem, type, handler){
		if (elem.addEventListener) {
			elem.addEventListener(type, handler, false);
		} else if(elem.attachEvent){
			//IE
			elem.attachEvent("on" + type, handler);
		}else{
			elem["on" + type] = handler;
		};
	},
	//删除事件
	unbind: function(elem, type ,handler){
		if (elem.removeEventListener) {
			elem.removeEventListener(type, handler, false);
		} else if(elem.detachEvent){
			//IE
			elem.detachEvent("on" + type, handler)
		}else{
			elem["on" + type] = handler;
		};
	},
	//获取事件
	getEvent: function(event){
		return event ? event : window.event;
	},
	//获取事件目标
	getTarget: function(event){
		return event.target || event.srcElement;
	},
	//相关元素
	relatedTarget: function(event){
		if (event.relatedTarget) {
			return event.relatedTarget;
		} else if (event.toElement){
			return event.toElement;
		} else if (event.formElement) {
			return event.formElement;
		} else {
			return null;
		};
	},
	//阻止默认行为
	preventDefault: function(event){
		if(event.preventDefault){
			event.preventDefault();
		}else{
			event.returnValue = false;
		}
	},
	//取消捕获/冒泡
	cancelBubble: function(event){
		if (event.stopPropagation) {
			event.stopPropagation();
		} else{
			event.cancelBubble = true;
		};
	},
	//获取鼠标按钮
	getMouseButton: function(event){
		if (document.implementation.hasFeature("MouseEvents", "2.0")) {
			return event.button;
		} else{
			switch (event.button){
				case 0:
				case 1:
				case 3:
				case 5:
				case 7:
					return 0;
				case 2:
				case 6:
					return 2;
				case 4:
					return 1;
			}
		};
	},
	//获取键盘code
	getCharCode: function(event){
		if (typeof event.charCode == "number") {
			console.log('char code');
			return event.charCode;
		} else{
			return event.keyCode;
		};
	},
	getDirection: function(event){
		var keyCode = event.which || event.keyCode;
		switch(keyCode){
			case 1:
			case 38:
			case 269: //up
				return 'up';
				break;
			case 2:
			case 40:
			case 270:
				return 'down';
				break;
			case 3:
			case 37:
			case 271:
				return 'left';
				break;
			case 4:
			case 39:
			case 272:
				return 'right';
				break;
			case 339: //exit
			case 240: //back
				return 'back';
				break;
		}
	}
};
</script>
<script type="text/javascript">
(function(){
    // canvas
    var canvas = document.getElementById('demo');
    var ctx = canvas.getContext('2d');

    //player base
    var playerImage = new Image();
    playerImage.src = 'go.png';
    var player = {
        x: 50,       // 在canvas中的坐标
        y: 0,
        imageX: 0,  // 图像定位坐标
        imageY: 0,
        width: 50,  // 图像显示区域大小
        height: 60,
        stop: true  // 是否停止
    };

    function clean () {
        // clear canvas
        ctx.clearRect(0, 0, canvas.width, canvas.height);
    }

    function playerInit () {
        // init player
        playerImage.onload = _drawPlayer;
    }

    function playerMove (value) {
        if('right' === value){
            // move right
            if (player.stop) {
                player.imageX += 50;
            }else{
                player.imageX = 0;
            }
            if (player.imageX >= 150) {
                player.imageX = 0;
            };
            // player move speed
            player.x += 5;
            player.imageY = 0;

        } else if ('left' === value){
            // move left
            if (player.stop) {
                player.imageX += 50;
            }else{
                player.imageX = 0;
            }
            if (player.imageX >= 150) {
                player.imageX = 0;
            };
            // player move speed
            player.x -= 5;
            player.imageY = 60;
        };

        clean();
        _drawPlayer();
    }

    function playerJump (value) {
        // player jump
    }

    function _drawPlayer () {
        // draw player image
        ctx.drawImage(playerImage, player.imageX, player.imageY, player.width, player.height, player.x, canvas.height - player.height, player.width, player.height);
    }

    function playerAction (value) {
        var posX = 0;
        var posY = 0;
        // console.log(player.x);
        switch(value){
            case 'up':
                playerJump();
                break;
            case 'right':
                posX = player.x + player.width;
                if (posX >= canvas.width) {
                    return;
                };
                //player.x += 5;
                playerMove(value);
                break;
            case 'down':
                break;
            case 'left':
                if (player.x < 5) {
                    return;
                };
                //player.x -= 5;
                playerMove(value);
                break;
        };
        // console.log(player.x);
        return {x: player.x, y: player.y};
    }

    //init canvas
    var init = (function(options){
        options = options || {};
        canvas.width = options.width || 500;
        canvas.height = options.height || 300;

        //init draw rect
        playerInit();

        //bind user event
        eventjs.bind(document, 'keydown', function(event){
            var d = eventjs.getDirection(event);
            player.stop = true;
            playerAction(d);
        });
        eventjs.bind(document, 'keyup', function(event){
            var d = eventjs.getDirection(event);
            player.stop = false;
            playerAction(d);
        });
    })({width:800, height:400});

})();
</script>
</html>