练习题 - 1.1 ~~~ //下面那些符合命名规则 var a%=20 var 1a=20 var _a=40; var $a=30 ~~~ - 1.2 ~~~ console.log(""||"abc"); //"abc" console.log(0 == ''); //true function b(){ } console.log(typeof b);//function ~~~ - 1.3 ~~~ var x = "2"+3+4; ~~~ - 1.4 ~~~ var value = 0; if(value){ console.log("true") }else{ console.log("fasle") } ~~~ - 1.5 ~~~ var x=!false; var y; if(x==true){ y = true }else{ y = false } alert(y); ~~~ - 1.6 ~~~ var b = 10,c=3; if((b%c)>=2){ alert("a") }else{ alert("b") } ~~~ - 1.7 ~~~ var x = 1; var y =x+x++; alert(y); ~~~ - 1.8 ~~~ 1.typeof能得到哪些类型 2.===和==的区别 ~~~ - 1.9JS中的内置对象 ~~~ Object, Array, Function, Number, String, Boolean, Date, RegExp, Error ~~~ - 1.10`Boolean`值有哪些情况为false - 1.11 ~~~ 100 == '100' 0 == '' null == undefined ~~~