``` var c=true; if($(".product-select-text").css('color','red'),false,b){ console.log(5555) } 相當于 : $(".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]當if沒有大括號且條件不滿足時,條件后面第一條語句(第一個分號;前面的語句)不會執行,但后面語句正常執行 ``` 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 ```