Javascript jQuery 快捷键插件 Firefox热键屏蔽

//usage:$(dom).keyman({key:"D",ctrl:true,callback:func});$.fn.keyman = Keyman;function Keyman( opts ){    var CTRL = opts.ctrl||false;    var SHIFT = opts.shift||false;    var ALT = opts.alt||false;    var key = opts.key||null;    if(key instanceof String || typeof key=="string"){        key = key.charCodeAt(0);    }else if ( !isNaN(key) ){        key = parseInt(key);    }    var begin = "a".charCodeAt(0);    var end = "z".charCodeAt(0);    var gap = begin-"A".charCodeAt(0);    if(key>=begin && key<=end) key -= gap;    if(!key||!opts.callback) return this;    this.live("keydown",function(e){        if( CTRL==e.ctrlKey&&SHIFT==e.shiftKey&&key==e.keyCode){            var r = opts.callback(e);            if(e.preventDefault) e.preventDefault();            if(e.stopPropagation) e.stopPropagation();            e.cancelBubble = true;            e.returnValue = false;            e.keyCode = 0;            return r;        }    });}