鼠标的拖拽事件
拖拽的流程：
（1）onmousedown：当鼠标在被拖拽元素上按下时，开始拖拽；
（2）onmousemove：当鼠标移动时被拖拽元素跟随鼠标移动；
（3）onmouseup：当鼠标松开时，被拖拽元素固定在当前位置。
鼠标的滚轮事件
onmousewheel：鼠标滚轮滚动的事件，会在滚轮滚动时触发。但是火狐不支持该属性。
DOMMouseScroll：在火狐中需要使用 DOMMouseScroll 来绑定滚动事件。注意该事件需要通过addEventListener()函数来绑定。
键盘事件
事件名
onkeydown：按键被按下。
onkeyup：按键被松开。
注意：
如果一直按着某一个按键不松手，那么，
onkeydown事件会一直触发。此时，松开键盘，onkeyup事件会执行一次。当
onkeydown连续触发时，第一次和第二次之间会间隔稍微长一点，后续的间隔会非常快。这种设计是为了防止误操作的发生。
键盘事件一般都会绑定给一些可以获取到焦点的对象或者是document。代码举例：
<span style="background-color:#f8f8f8"><span style="color:#333333"> <span style="color:#117700"><</span><span style="color:#117700">body</span><span style="color:#117700">></span>
<span style="color:#117700"><</span><span style="color:#117700">script</span><span style="color:#117700">></span>
<span style="color:#000000">document</span>.<span style="color:#000000">onkeydown</span> <span style="color:#981a1a">=</span> <span style="color:#770088">function</span>(<span style="color:#0000ff">event</span>) {
<span style="color:#0055aa">event</span> <span style="color:#981a1a">=</span> <span style="color:#0055aa">event</span> <span style="color:#981a1a">||</span> <span style="color:#000000">window</span>.<span style="color:#000000">event</span>;
<span style="color:#000000">console</span>.<span style="color:#000000">log</span>(<span style="color:#aa1111">'qianguyihao 键盘按下了'</span>);
};
<span style="color:#000000">document</span>.<span style="color:#000000">onkeyup</span> <span style="color:#981a1a">=</span> <span style="color:#770088">function</span>() {
<span style="color:#000000">console</span>.<span style="color:#000000">log</span>(<span style="color:#aa1111">'qianguyihao 键盘松开了'</span>);
};
<span style="color:#117700"></</span><span style="color:#117700">script</span><span style="color:#117700">></span>
<span style="color:#117700"><</span><span style="color:#117700">input</span> <span style="color:#0000cc">type</span>=<span style="color:#aa1111">"text"</span> <span style="color:#117700">/></span>
<span style="color:#117700"></</span><span style="color:#117700">body</span><span style="color:#117700">></span></span></span>判断哪个键盘被按下
可以通过event事件对象的keyCode来获取按键的编码。
此外，event事件对象里面还提供了以下几个属性：
altKey
ctrlKey
shiftKey
上面这三个属性，可以用来判断alt、ctrl、和shift是否被按下。如果按下则返回true，否则返回false。代码举例：
<span style="background-color:#f8f8f8"><span style="color:#333333"> <span style="color:#117700"><</span><span style="color:#117700">body</span><span style="color:#117700">></span>
<span style="color:#117700"><</span><span style="color:#117700">script</span><span style="color:#117700">></span>
<span style="color:#000000">document</span>.<span style="color:#000000">onkeydown</span> <span style="color:#981a1a">=</span> <span style="color:#770088">function</span>(<span style="color:#0000ff">event</span>) {
<span style="color:#0055aa">event</span> <span style="color:#981a1a">=</span> <span style="color:#0055aa">event</span> <span style="color:#981a1a">||</span> <span style="color:#000000">window</span>.<span style="color:#000000">event</span>;
<span style="color:#000000">console</span>.<span style="color:#000000">log</span>(<span style="color:#aa1111">'qianguyihao：键盘按下了'</span>);
<span style="color:#aa5500">// 判断y和ctrl是否同时被按下</span>
<span style="color:#770088">if</span> (<span style="color:#0055aa">event</span>.<span style="color:#000000">ctrlKey</span> <span style="color:#981a1a">&&</span> <span style="color:#0055aa">event</span>.<span style="color:#000000">keyCode</span> <span style="color:#981a1a">===</span> <span style="color:#116644">89</span>) {
<span style="color:#000000">console</span>.<span style="color:#000000">log</span>(<span style="color:#aa1111">'ctrl和y都被按下了'</span>);
}
};
<span style="color:#117700"></</span><span style="color:#117700">script</span><span style="color:#117700">></span>
<span style="color:#117700"></</span><span style="color:#117700">body</span><span style="color:#117700">></span></span></span>举例：input 文本框中，禁止输入数字。代码实现：
<span style="background-color:#f8f8f8"><span style="color:#333333"> <span style="color:#117700"><</span><span style="color:#117700">body</span><span style="color:#117700">></span>
<span style="color:#117700"><</span><span style="color:#117700">input</span> <span style="color:#0000cc">type</span>=<span style="color:#aa1111">"text"</span> <span style="color:#117700">/></span>
<span style="color:#117700"><</span><span style="color:#117700">script</span><span style="color:#117700">></span>
<span style="color:#aa5500">//获取input</span>
<span style="color:#770088">var</span> <span style="color:#0000ff">input</span> <span style="color:#981a1a">=</span> <span style="color:#000000">document</span>.<span style="color:#000000">getElementsByTagName</span>(<span style="color:#aa1111">'input'</span>)[<span style="color:#116644">0</span>];
<span style="color:#000000">input</span>.<span style="color:#000000">onkeydown</span> <span style="color:#981a1a">=</span> <span style="color:#770088">function</span>(<span style="color:#0000ff">event</span>) {
<span style="color:#0055aa">event</span> <span style="color:#981a1a">=</span> <span style="color:#0055aa">event</span> <span style="color:#981a1a">||</span> <span style="color:#000000">window</span>.<span style="color:#000000">event</span>;
<span style="color:#aa5500">//console.log('qianguyihao:' + event.keyCode);</span>
<span style="color:#aa5500">//数字 48 - 57</span>
<span style="color:#aa5500">//使文本框中不能输入数字</span>
<span style="color:#770088">if</span> (<span style="color:#0055aa">event</span>.<span style="color:#000000">keyCode</span> <span style="color:#981a1a">>=</span> <span style="color:#116644">48</span> <span style="color:#981a1a">&&</span> <span style="color:#0055aa">event</span>.<span style="color:#000000">keyCode</span> <span style="color:#981a1a"><=</span> <span style="color:#116644">57</span>) {
<span style="color:#aa5500">//在文本框中输入内容，属于onkeydown的默认行为</span>
<span style="color:#770088">return</span> <span style="color:#221199">false</span>; <span style="color:#aa5500">// 如果在onkeydown中取消了默认行为，则输入的内容，不会出现在文本框中</span>
}
};
<span style="color:#117700"></</span><span style="color:#117700">script</span><span style="color:#117700">></span>
<span style="color:#117700"></</span><span style="color:#117700">body</span><span style="color:#117700">></span>
</span></span>举例：通过键盘的方向键，移动盒子
代码实现：
<span style="background-color:#f8f8f8"><span style="color:#333333"> <span style="color:#555555"><!DOCTYPE html></span>
<span style="color:#117700"><</span><span style="color:#117700">html</span><span style="color:#117700">></span>
<span style="color:#117700"><</span><span style="color:#117700">head</span><span style="color:#117700">></span>
<span style="color:#117700"><</span><span style="color:#117700">meta</span> <span style="color:#0000cc">charset</span>=<span style="color:#aa1111">"UTF-8"</span> <span style="color:#117700">/></span>
<span style="color:#117700"><</span><span style="color:#117700">title</span><span style="color:#117700">></</span><span style="color:#117700">title</span><span style="color:#117700">></span>
<span style="color:#117700"><</span><span style="color:#117700">style</span> <span style="color:#0000cc">type</span>=<span style="color:#aa1111">"text/css"</span><span style="color:#117700">></span>
<span style="color:#3300aa">#box1</span> {
<span style="color:#000000">width</span>: <span style="color:#116644">100px</span>;
<span style="color:#000000">height</span>: <span style="color:#116644">100px</span>;
<span style="color:#000000">background-color</span>: <span style="color:#770088">red</span>;
<span style="color:#000000">position</span>: <span style="color:#221199">absolute</span>;
}
<span style="color:#117700"></</span><span style="color:#117700">style</span><span style="color:#117700">></span>
<span style="color:#117700"></</span><span style="color:#117700">head</span><span style="color:#117700">></span>
<span style="color:#117700"><</span><span style="color:#117700">body</span><span style="color:#117700">></span>
<span style="color:#117700"><</span><span style="color:#117700">div</span> <span style="color:#0000cc">id</span>=<span style="color:#aa1111">"box1"</span><span style="color:#117700">></</span><span style="color:#117700">div</span><span style="color:#117700">></span>
<span style="color:#117700"><</span><span style="color:#117700">script</span> <span style="color:#0000cc">type</span>=<span style="color:#aa1111">"text/javascript"</span><span style="color:#117700">></span>
<span style="color:#aa5500">// 使div可以根据不同的方向键向不同的方向移动</span>
<span style="color:#aa5500">/*</span>
<span style="color:#aa5500"> * 按左键，div向左移</span>
<span style="color:#aa5500"> * 按右键，div向右移</span>
<span style="color:#aa5500"> * ...</span>
<span style="color:#aa5500"> */</span>
<span style="color:#aa5500">//为document绑定一个按键按下的事件</span>
<span style="color:#000000">document</span>.<span style="color:#000000">onkeydown</span> <span style="color:#981a1a">=</span> <span style="color:#770088">function</span>(<span style="color:#0000ff">event</span>) {
<span style="color:#0055aa">event</span> <span style="color:#981a1a">=</span> <span style="color:#0055aa">event</span> <span style="color:#981a1a">||</span> <span style="color:#000000">window</span>.<span style="color:#000000">event</span>;
<span style="color:#aa5500">//定义一个变量，来表示移动的速度</span>
<span style="color:#770088">var</span> <span style="color:#0000ff">speed</span> <span style="color:#981a1a">=</span> <span style="color:#116644">10</span>;
<span style="color:#aa5500">//当用户按了ctrl以后，速度加快</span>
<span style="color:#770088">if</span> (<span style="color:#0055aa">event</span>.<span style="color:#000000">ctrlKey</span>) {
<span style="color:#000000">console</span>.<span style="color:#000000">log</span>(<span style="color:#aa1111">'smyhvae ctrl'</span>);
<span style="color:#0055aa">speed</span> <span style="color:#981a1a">=</span> <span style="color:#116644">20</span>;
}
<span style="color:#aa5500">/*</span>
<span style="color:#aa5500"> * 37 左</span>
<span style="color:#aa5500"> * 38 上</span>
<span style="color:#aa5500"> * 39 右</span>
<span style="color:#aa5500"> * 40 下</span>
<span style="color:#aa5500"> */</span>
<span style="color:#770088">switch</span> (<span style="color:#0055aa">event</span>.<span style="color:#000000">keyCode</span>) {
<span style="color:#770088">case</span> <span style="color:#116644">37</span>:
<span style="color:#aa5500">//alert("向左"); left值减小</span>
<span style="color:#000000">box1</span>.<span style="color:#000000">style</span>.<span style="color:#000000">left</span> <span style="color:#981a1a">=</span> <span style="color:#000000">box1</span>.<span style="color:#000000">offsetLeft</span> <span style="color:#981a1a">-</span> <span style="color:#0055aa">speed</span> <span style="color:#981a1a">+</span> <span style="color:#aa1111">'px'</span>; <span style="color:#aa5500">// 在初始值的基础之上，减去 speed 大小</span>
<span style="color:#770088">break</span>;
<span style="color:#770088">case</span> <span style="color:#116644">39</span>:
<span style="color:#aa5500">//alert("向右");</span>
<span style="color:#000000">box1</span>.<span style="color:#000000">style</span>.<span style="color:#000000">left</span> <span style="color:#981a1a">=</span> <span style="color:#000000">box1</span>.<span style="color:#000000">offsetLeft</span> <span style="color:#981a1a">+</span> <span style="color:#0055aa">speed</span> <span style="color:#981a1a">+</span> <span style="color:#aa1111">'px'</span>;
<span style="color:#770088">break</span>;
<span style="color:#770088">case</span> <span style="color:#116644">38</span>:
<span style="color:#aa5500">//alert("向上");</span>
<span style="color:#000000">box1</span>.<span style="color:#000000">style</span>.<span style="color:#000000">top</span> <span style="color:#981a1a">=</span> <span style="color:#000000">box1</span>.<span style="color:#000000">offsetTop</span> <span style="color:#981a1a">-</span> <span style="color:#0055aa">speed</span> <span style="color:#981a1a">+</span> <span style="color:#aa1111">'px'</span>;
<span style="color:#770088">break</span>;
<span style="color:#770088">case</span> <span style="color:#116644">40</span>:
<span style="color:#aa5500">//alert("向下");</span>
<span style="color:#000000">box1</span>.<span style="color:#000000">style</span>.<span style="color:#000000">top</span> <span style="color:#981a1a">=</span> <span style="color:#000000">box1</span>.<span style="color:#000000">offsetTop</span> <span style="color:#981a1a">+</span> <span style="color:#0055aa">speed</span> <span style="color:#981a1a">+</span> <span style="color:#aa1111">'px'</span>;
<span style="color:#770088">break</span>;
}
};
<span style="color:#117700"></</span><span style="color:#117700">script</span><span style="color:#117700">></span>
<span style="color:#117700"></</span><span style="color:#117700">body</span><span style="color:#117700">></span>
<span style="color:#117700"></</span><span style="color:#117700">html</span><span style="color:#117700">></span>
</span></span>上方代码，待改进的地方：
（1）移动盒子时，如果要加速，需要先按方向键，再按Ctrl键。
（2）首次移动盒子时，动作较慢。后续如果学习了定时器相关的内容，可以再改进。