004数据类型转换.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>数据类型转换</title>
    <script>
        //------------------------------类型转换--------------------------------------

        //-----------------------------其他类型转数字类型--------------------------------
        //三种方式转换：
        //1、parseInt:转整数
        console.log(parseInt("10"));    //字符串类型转为数字类型 10
        console.log(parseInt("10a"));   //10
        console.log(parseInt("g10"));   //NaN
        console.log(parseInt("1cbsbkb"));   //1
        console.log(parseInt("10.1213"));   //10
        //2、parseFloat()   转小数
        console.log(parseFloat("10"));   //10
        console.log(parseFloat("10a"));   //10
        console.log(parseFloat("g10"));   //NaN
        console.log(parseFloat("1cbsbkb"));   //1
        console.log(parseFloat("10.12sjkj"));    //10.12
        //3、Number()转数字
        console.log(Number("10"));   //10
        console.log(Number("10a"));   //10
        console.log(Number("g10"));   //NaN
        console.log(Number("1cbsbkb"));   //1
        console.log(Number("10.12sjkj"));    //10.12

        //------------------------------其他类型转字符串类型-----------------------------
        // .1、  toString()    变量要有意义（有赋值）
        // 2、String()        变量没有意义（没有赋值）
        var num = 10;
        console.log(num.toString())
        var num1;
        var num2=null;
        console.log(String(num2));

        //------------------------------其他类型转布尔类型--------------------------------
        console.log(Boolean(1));  //true
        console.log(Boolean(0));  //false
        console.log(Boolean(11));   //true
        console.log(Boolean(-11));   //true
        console.log(Boolean("哈哈"));   //true
        console.log(Boolean(""));    //false
        console.log(Boolean("null"));   //true
        console.log(Boolean("undefined"));  //true

    </script>
</head>
<body>

</body>
</html>
004数据类型转换.html

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