//变量 要声明 /*"use strict"; a='liuynag'; console.log(a);//Uncaught ReferenceError: a is not defined*///不能调用delete // "use strict"; /*var color='red'; console.log(color); delete color;//Delete of an unqualified identifier in strict mode. console.log(color);*///不能将保留字作为变量名 /* "use strict"; var public='hah'; console.log(public);//Unexpected strict mode reserved Word*///严格模式 对象重名属性报错 /*"use strict"; var person={ name:'hahhha', name:'greg' } console.log(person.name);//编辑器报错，浏览器没有*///重名参数 /*"use strict"; function a(num,num){ console.log(num);// Duplicate parameter name not allowed in this context console.log(arguments[1]); console.log(a.length); } a(11,12);*///arguments对象 // "use strict"; /*function a(num,num1){ num=2; console.log(arguments[0]);//严格11 不严格 2 } a(11,12);*///淘汰了arguments.callee arguments.caller // "use strict" /*function factorial(num){ if(num<=1){ return 1; }else{ return num*arguments.callee(num-1); } } console.log(factorial(5));//'caller', 'callee', and 'arguments' PRoperties may not be accessed on strict mode functions or the arguments objects for calls to them*///严格模式下 if语句不能创建函数 预编译不会提到if语句外 /*"use strict" if(true){ function dosomething(){ console.log("好像没出错"); } }else{ //写完 } dosomething();//ReferenceError: dosomething is not defined*///eval()，它将不再包含上下文中创建函数或者变量； /*"use strict" function dosomething(){ eval("var x=10"); console.log(x);//: x is not defined } dosomething()*///eval()在严格模式下只有在被求值的特殊作用域下有效，随后被销毁 /*"use strict" var result=eval("var x=10,y=11;x+y"); alert(result);//21*///抑制this /*"use strict" var color='red'; function color1(){ console.log(this.color); } color1(null);//严格Cannot read property 'color' of undefined 不严格 red*///抛弃了with语句 /*"use strict" with(location){ alert(href);////严格Strict mode code may not include a with statement不严格 一段地址 }*///抛弃8进制，0开头不属于8进制 /*"use strict"; var value='010'; console.log(parseInt(value));//不严格8 严格10*/
