27js基础，数据类型转换

<head>
    <meta charset="UTF-8">
    <title>6js数据类型转换</title>
</head>
<body>
        <script>
            //1：普通转换
            //将数据转换成整数，parseInt(参数);
             var n1 = "100"
                 , n2 = "100.1"
                 , n3 = "10a0.9"
                 , n4 = "t10a0.9";
             document.writeln(n1+">>>>>"+parseInt(n1)+"<br>");
             document.writeln(n2+">>>>>"+parseInt(n2)+"<br>");
             document.writeln(n3+">>>>>"+parseInt(n3)+"<br>");
             document.writeln(n4+">>>>>"+parseInt(n4)+"<br>");
             /*
             100>>>>>100
             100.1>>>>>100
             10a0.9>>>>>10
             t10a0.9>>>>>NaN
             * */
            document.writeln("<hr>");
            //将数据转换成浮点,parseFloat(参数)
            document.writeln(n1+">>>>>"+parseFloat(n1)+"<br>");
            document.writeln(n2+">>>>>"+parseFloat(n2)+"<br>");
            document.writeln(n3+">>>>>"+parseFloat(n3)+"<br>");
            document.writeln(n4+">>>>>"+parseFloat(n4)+"<br>");
            document.writeln("<hr>");
            //2:强制类型转换
            //强转成数值：Number(参数);
            document.writeln(n1+">>>>>"+Number(n1)+"<br>");
            document.writeln(n2+">>>>>"+Number(n2)+"<br>");
            document.writeln(n3+">>>>>"+Number(n3)+"<br>");
            document.writeln(n4+">>>>>"+Number(n4)+"<br>");
            document.writeln("<hr>");
            //强转成布尔:Boolean(参数)
            /*
            * 1：为false的情况
            *       数值：0
            *       字符串：""
            *       变量未赋值
            *       变量值:null
            * 2:其它情况均为true
            * */

            var str1 = 0
                , str2 = ""
                , str3
                , str4 = null
            document.writeln(n1+">>>>>"+Boolean(str1)+"<br>");
            document.writeln(n2+">>>>>"+Boolean(str2)+"<br>");
            document.writeln(n3+">>>>>"+Boolean(str3)+"<br>");
            document.writeln(n4+">>>>>"+Boolean(str4)+"<br>");
            document.writeln("<hr>");
        </script>
</body>
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100>>>>>100
100.1>>>>>100
10a0.9>>>>>10
t10a0.9>>>>>NaN

100>>>>>100
100.1>>>>>100.1
10a0.9>>>>>10
t10a0.9>>>>>NaN

100>>>>>100
100.1>>>>>100.1
10a0.9>>>>>NaN
t10a0.9>>>>>NaN

100>>>>>false
100.1>>>>>false
10a0.9>>>>>false
t10a0.9>>>>>false

posted on 2022-04-10 14:09 小小程序猿level1 阅读(32) 评论(0) 收藏举报