首页 > Web开发 > 详细

js数据强转

时间:2020-03-31 22:11:37      阅读:58      评论:0      收藏:0      [点我收藏+]
<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
        <script type="text/javascript">
            /* 强转 */
            /* 1.其他类型转为Number类型 */
            var s1 = "10";
            var s2 = "abc";
            var b1 = false;
            var o1 = Object(10);
            var o2 = new Array();
            o2[0]=1;
            o2[1]=2;
            var o3 = null;
            document.write("String转number,可转:"+Number(s1)+"<br>");//10
            document.write("String转number,不可转:"+Number(s2)+"<br>");//Nan
            document.write("boolean转number,可转:"+Number(b1)+"<br>");//0
            document.write("Object转number=:"+Number(o2)+"<br>");//若o2中只有o2[0],则为1,若还有o2[1],则为NaN
            document.write("null转number:"+Number(o3)+"<br>");//0
            /* 能转就转,不能转就为NaN, */
            /* 2.其他类型转为boolean类型 */
            var nb = 10;
            var sb = "abc";
            var ob = new Object(1);
            var unb;
            //2.1Number转Boolean
            document.write("Number转Boolean:"+Boolean(nb)+"<br>");//非零转成true,0转成false
            //2.2String转Boolean
            document.write("String转Boolean:"+Boolean(sb)+"<br>");//非空转成true,空转成false
            //2.3Object转Boolean
            document.write("Object转Boolean:"+Boolean(ob)+"<br>");//非null转成true,null转成false
            //2.4声明未赋值(undefined)转Boolean
            document.write("声明未赋值(undefined)转Boolean:"+Boolean(unb)+"<br>");//false
</script> </head> <body> </body> </html>

 

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
        <script type="text/javascript">
            /* 3.boolean转String */
            var b = true;
            document.write("Boolean转String:"+typeof(b.toString())+"<br>");//String
            /* 4.String转Number */
            var s = "10";
            document.write("String转Number:"+typeof(parseInt(s) )+"<br>");//number
        </script>
    </head>
    <body>
    </body>
</html>

 

js数据强转

原文:https://www.cnblogs.com/qilin20/p/12599116.html

(0)
(0)
   
举报
评论 一句话评论(0
关于我们 - 联系我们 - 留言反馈 - 联系我们:wmxa8@hotmail.com
© 2014 bubuko.com 版权所有
打开技术之扣,分享程序人生!