JS第四课(运算符)（一）

 <!-- 第一部分 算式运算符 -->
 <h1>算式运算符 </h1>
 <script>
     console.log("算式运算符")
     // 算数运算符一
     console.log(2 + 2);
     console.log(2 / 2);
     console.log(2 * 2);
     console.log(2 - 2);
     console.log(8 % 2);
     //算数运算符二
     var num1 = 2000
     var num2 = 100
     document.write("<h1>" + num1 + num2 + "</h1>")
     document.write(num1 - num2)
     document.write("<h1>" + num1 * num2 + "</h1>")
     document.write("<h1>" + num1 / num2 + "</h1>")
     document.write("<h1>" + num1 % num2 + "</h1>")
     document.write("<h1>" + num1++ + "</h1>")
     document.write("<h1>" + ++num1 + "</h1>")
     document.write("<h1>" + num2-- + "</h1>")
 </script>

 <!-- 第三部分 比较运算符 Boolean类型 -->
 <script>
     console.log("比较运算符 Boolean类型")
     var aa = 12;
     var bb = 4;
     console.log(aa == bb)
     console.log(aa > bb)
     console.log(aa < bb)
     console.log(aa >= bb)
     console.log(aa <= bb)
     console.log(aa != bb)
     console.log(aa!==bb)
 </script>

 <!-- 逻辑运算符 -->
 <script>
     //逻辑运算符 boolean 与或非
     console.log(3 > 5 && 3 > 2);
     console.log(32 > 53 && 32 < 2);
     console.log(3 > 5 || 3 > 2);
     console.log(true);
     //逻辑短路
     console.log(123 && 4567);
     console.log(0 && 4567);
     console.log(0 && 1 + 2 && 456 * 89889);
     //逻辑或短路
     console.log(123 || 456);
     var aa = 123;
     var bb = 234;
     var cc = 123;
     console.log(aa = cc)
     console.log(aa == cc)
     console.log(aa == cc)
     console.log("等于号的区别")
     alert("逻辑运算符||")
     console.log(!true);
     console.log(!false);
 </script>

<!--第二部分  赋值运算符 -->
<script>
    console.log("赋值运算符")
    var a = 20;
    var b = 5;
    console.log("+等于" + (a += b));
    console.log("-等于" + (a -= b));
    console.log("*等于" + (a *= b));
    console.log("%等于" + (a %= b));
    console.log("/等于" + (a /= b));
</script>