``` var c=true; if($(".product-select-text").css('color','red'),false,b){ console.log(5555) } 相当于 : $(".product-select-text").css('color','red') false; if(b){ console.log(5555) } ``` ``` var a,b,c; if (1==2) {a=10;b=20;c=30} console.log(a);//undefined console.log(b);//undefined console.log(c);//undefined ``` >[danger]当if没有大括号且条件不满足时,条件后面第一条语句(第一个分号;前面的语句)不会执行,但后面语句正常执行 ``` var a,b,c; if (1==2) a=10;b=20;c=30; console.log(a);//undefined console.log(b);//20 console.log(c);//30 ``` ``` var a,b,c; if (1==2) { console.log('xxxxx'); }else a=10;b=20;c=30; console.log(a);//10 console.log(b);//20 console.log(c);//30 ``` ``` var a,b,c; if (1==1) { }else a=10;b=20;c=30; console.log(a);//undefined console.log(b);//20 ``` ``` var a,b,c; if (1==1) a=10;b=20;c=30; console.log(a);//10 console.log(b);//20 console.log(c);//30 ```