熟悉Javascr ipt的数据类型：

　　数值型、字符型、逻辑型、空值



掌握Javascr ipt的表达式与运算符



掌握Javascr ipt控制语句、内部对象



掌握Javascr ipt自定义对象-Familiar with the Javascr ipt data types: numeric, character, logic type, null values have Javascr ipt expressions and operators have Javascr ipt control statements, internal objects have custom Javascr ipt object