java web-2.5JavaScript语法流程控制语句

傷城~ 2023-07-08 11:30 25阅读 0赞

## 流程控制语句 ##

1.if...else (与java 一样)
    2.switch 
    3.while
    4.do...while
    5.for

**if…else**:  
用法与java一样  
**switch**：

*  在java中，switch语句可以接受的数据类型：byte，int，shot，char，枚举1.5，String1.7

switch（变量）：
          case 值：

*  在js中，switch语句可以接受任意的原始数据类型  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70]  
    **while**  
    用法与java一样  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70 1]  
    **do…while**  
    **for**  
    用法与java一样，注意写法  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70 2]

## 练习-99乘法表 ##

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>99乘法表</title>
    
       
        <style>
            td{ 
                border: 1px solid;
            }
        </style>
    
        <script>
            //加边框
            document.write("<table align = 'center'>");
    
            //99乘法表循环
            for(var i = 1;i <= 9;i ++){ 
                document.write("<tr>");
                for(var j = 1;j <= i;j ++){ 
                    document.write("<td>");
                    document.write(i + "*" + j  + "=" + (i*j) + "   ");
                    document.write("</td>")
                }
                document.write("</tr>")
            }
    
            document.write("</table>")
    
    
    
        </script>
    </head>
    <body>
    
    </body>
    </html>

结果显示  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70 3]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200227084351971.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200227084601838.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20200227084821863.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20200227085723378.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ==,size_16,color_FFFFFF,t_70