ECMAScript的關鍵字：
break,else,new,var,case,finally,return,void,catch,for,switch,while,continute,function,this,with,default,if,throw,delete,in,try,do,instanceof,typeof,
第三版保留字：
abstract enum int short
boolean export interface static
byte extends long super
char final native synchronized
class float package throws
const goto private transient
debugger implements protected volatile
double import public