JS的Event对象是触发事件的时候传递给事件处理函数的一个对象，这个对象中存在触发事件的基本信息。如：触发事件的事件源、键盘码（如果存在）等基本信息。
1、通过event.type获取事件的类型
<script>
$(function(){
$("a").click(function(event) {
alert(event.type);//获取事件类型
//return false;//阻止链接跳转
event.preventDefault();
});
})
</script>
2、获取事件目标的属性值
html部分代码如下：
<body> <a href='http://google.com'>click me .</a> </body>
<script>
$(function(){
$("a[href=http://google.com]").click(function(event) {
alert(event.target.href);//获取触发事件的<a>元素的href属性值
return false;//阻止链接跳转
});
})
</script>
可以获取到属性href的值为‘http://google.com'。
3、获取鼠标对应的坐标值x与y
<script>
$(function(){
$("a").click(function(e) {
alert("Current mouse position: " + e.pageX + ", " + e.pageY );//获取鼠标当前相对于页面的坐标
return false;//阻止链接跳转
});
})
</script>
这里传递的参数名不一定非要是event，可以是任意的名称，只要后面的相对应就可以。默认传入的值为event。如果你不给参数的话，就会默认传入一个叫event的参数。
4、which属性可以获取相应的事件对应的值
which 属性指示按了哪个键或按钮。
<script>
$(function(){
$("a").mousedown(function(e){
alert(e.which) // 1 = 鼠标左键 left; 2 = 鼠标中键; 3 = 鼠标右键
return false;//阻止链接跳转
})
})
</script>
关于如何得到一个键在Javascript中的Keycode值，可以参考：
keycode 8 = BackSpace BackSpace keycode 9 = Tab Tab keycode 12 = Clear keycode 13 = Enter keycode 16 = Shift_L keycode 17 = Control_L keycode 18 = Alt_L keycode 19 = Pause keycode 20 = Caps_Lock keycode 27 = Escape Escape keycode 32 = space space keycode 33 = Prior keycode 34 = Next keycode 35 = End keycode 36 = Home keycode 37 = Left keycode 38 = Up keycode 39 = Right keycode 40 = Down keycode 41 = Select keycode 42 = Print keycode 43 = Execute keycode 45 = Insert keycode 46 = Delete keycode 47 = Help keycode 48 = 0 equal braceright keycode 49 = 1 exclam onesuperior keycode 50 = 2 quotedbl twosuperior keycode 51 = 3 section threesuperior keycode 52 = 4 dollar keycode 53 = 5 percent keycode 54 = 6 ampersand keycode 55 = 7 slash braceleft keycode 56 = 8 parenleft bracketleft keycode 57 = 9 parenright bracketright keycode 65 = a A keycode 66 = b B keycode 67 = c C keycode 68 = d D keycode 69 = e E EuroSign keycode 70 = f F keycode 71 = g G keycode 72 = h H keycode 73 = i I keycode 74 = j J keycode 75 = k K keycode 76 = l L keycode 77 = m M mu keycode 78 = n N keycode 79 = o O keycode 80 = p P keycode 81 = q Q at keycode 82 = r R keycode 83 = s S keycode 84 = t T keycode 85 = u U keycode 86 = v V keycode 87 = w W keycode 88 = x X keycode 89 = y Y keycode 90 = z Z keycode 96 = KP_0 KP_0 keycode 97 = KP_1 KP_1 keycode 98 = KP_2 KP_2 keycode 99 = KP_3 KP_3 keycode 100 = KP_4 KP_4 keycode 101 = KP_5 KP_5 keycode 102 = KP_6 KP_6 keycode 103 = KP_7 KP_7 keycode 104 = KP_8 KP_8 keycode 105 = KP_9 KP_9 keycode 106 = KP_Multiply KP_Multiply keycode 107 = KP_Add KP_Add keycode 108 = KP_Separator KP_Separator keycode 109 = KP_Subtract KP_Subtract keycode 110 = KP_Decimal KP_Decimal keycode 111 = KP_Divide KP_Divide keycode 112 = F1 keycode 113 = F2 keycode 114 = F3 keycode 115 = F4 keycode 116 = F5 keycode 117 = F6 keycode 118 = F7 keycode 119 = F8 keycode 120 = F9 keycode 121 = F10 keycode 122 = F11 keycode 123 = F12 keycode 124 = F13 keycode 125 = F14 keycode 126 = F15 keycode 127 = F16 keycode 128 = F17 keycode 129 = F18 keycode 130 = F19 keycode 131 = F20 keycode 132 = F21 keycode 133 = F22 keycode 134 = F23 keycode 135 = F24 keycode 136 = Num_Lock keycode 137 = Scroll_Lock keycode 187 = acute grave keycode 188 = comma semicolon keycode 189 = minus underscore keycode 190 = period colon keycode 192 = numbersign apostrophe keycode 210 = plusminus hyphen macron keycode 212 = copyright registered keycode 213 = guillemotleft guillemotright keycode 214 = masculine ordfeminine keycode 215 = ae AE keycode 216 = cent yen keycode 217 = questiondown exclamdown keycode 218 = onequarter onehalf threequarters keycode 220 = less greater bar keycode 221 = plus asterisk asciitilde keycode 227 = multiply division keycode 228 = acircumflex Acircumflex keycode 229 = ecircumflex Ecircumflex keycode 230 = icircumflex Icircumflex keycode 231 = ocircumflex Ocircumflex keycode 232 = ucircumflex Ucircumflex keycode 233 = ntilde Ntilde keycode 234 = yacute Yacute keycode 235 = oslash Ooblique keycode 236 = aring Aring keycode 237 = ccedilla Ccedilla keycode 238 = thorn THORN keycode 239 = eth ETH keycode 240 = diaeresis cedilla currency keycode 241 = agrave Agrave atilde Atilde keycode 242 = egrave Egrave keycode 243 = igrave Igrave keycode 244 = ograve Ograve otilde Otilde keycode 245 = ugrave Ugrave keycode 246 = adiaeresis Adiaeresis keycode 247 = ediaeresis Ediaeresis keycode 248 = idiaeresis Idiaeresis keycode 249 = odiaeresis Odiaeresis keycode 250 = udiaeresis Udiaeresis keycode 251 = ssharp question backslash keycode 252 = asciicircum degree keycode 253 = 3 sterling keycode 254 = Mode_switch
以上是js中的键值参考，其中比较重要的有13（enter），32（空格），27（ESC），16（Shift），17（Ctrl），18（Alt）。
更多的值可以通过下面的jQuery来获取：
<script>
$(function(){
$("input").keyup(function(e){//获取keyup时间的值
alert(e.which);
})
})
</script>