26js基础，运算符

<head>
    <meta charset="UTF-8">
    <title>5运算符</title>
</head>
<body>
        <script>
            //1:赋值运算符  "="
            //2:算术运算符 +，-，*，/,%，++，--
            var str = "10";

            document.writeln("str+3:"+(str+3)+"<br>");
            document.writeln("str-3:"+(str-3)+"<br>");
            document.writeln("str*3:"+(str*3)+"<br>");
            document.writeln("str/3:"+(str/3)+"<br>");
            document.writeln("str%3:"+(str%3)+"<br>");
            document.writeln("str++:"+(++str)+"<br>");
            document.writeln("str--:"+(--str)+"<br>");
            document.writeln("<hr>");

            //3:符合运算符 +=，-=，/=,*=,%=
            //4:关系运算符 >,<,>=,<=,!=,==,===,!==
            var n1 = "100"
                , n2 = 100;

            document.writeln(n1+"="+n2+"?"+(n1==n2));//==只比内容，不比类型
            document.writeln(n1+"="+n2+"?"+(n1===n2));//===比内容，也比类型
            document.writeln("<hr>");

            //5:逻辑运算符 &，|，！,^,&&,||,,,js中两边可以放任何数据类型
            var n3 = "apple"
                , n4;
            document.writeln("<br>");
            document.writeln("n3:"+n3+"<br>");
            document.writeln("n4:"+n4+"<hr>");

            n3 = n3||"无名氏"
            n4 = n4||"无名氏" //n4为负值：强转之后为false,所以n4="无名氏"
            document.writeln("n3:"+n3+"<br>");
            document.writeln("n4:"+n4+"<hr>");
            //6:三目运算符  表达式？值1:值2


        </script>


</body>
posted on 2022-04-10 12:57 小小程序猿level1 阅读(26) 评论(0) 收藏举报