JavaScript基础语法（输出语句）

以你之姓@ 2024-03-31 12:53 84阅读 0赞

## JavaScript基础语法（输出语句） ##

**学习路线**：[JavaScript基础语法（输出语句）][JavaScript]\->[JavaScript基础语法（变量）][JavaScript 1]\->[JavaScript基础语法（数据类型）][JavaScript 2]\->[JavaScript基础语法（运算符）][JavaScript 3]\->[JavaScript基础语法（流程控制语句）][JavaScript 4]\->[JavaScript基础语法（类型转换）][JavaScript 5]\->[JavaScript基础语法（函数）][JavaScript 6]\->[Array\_JavaScript][Array_JavaScript]\->[String\_JavaScript][String_JavaScript]\->[自定义对象\_JavaScript][JavaScript 7]\->[JavaScript\_BOM][JavaScript_BOM]\->[Window对象][Window]\->[confirm()、setInterval()、setTimeout()][confirm_setInterval_setTimeout]\->[History、Location][History_Location]\->[闪烁的灯泡][Link 1]\->[JavaScript\_DOM][JavaScript_DOM]\->[事件绑定(onclick,onfocus,onblur)][onclick_onfocus_onblur]\->  
[事件绑定(onmouseout,onmouseover)  
][onmouseout_onmouseover_]\->[事件绑定(onsubmit)表单提交  
][onsubmit_]\->[提交表单与验证表单案例  
][Link 2]

### 1.书写规范 ###

*  区分大小写：与 Java 一样，变量名、函数名以及其他一切东西都是区分大小写的
 *  每行结尾的分号可有可无
    
    如果一行上写多个语句时，必须加分号用来区分多个语句。
 *  注释
    
     *  单行注释：// 注释内容
     *  多行注释：/\* 注释内容 \*/
    
    > 注意：JavaScript 没有文档注释
 *  大括号表示代码块
    
    下面语句大家肯定能看懂，和 java 一样 大括号表示代码块。
    
        if (count == 3) {
               
           alert(count); 
        }

### 2 输出语句 ###

**简介**：js有3种输出的方法。

#### 使用 window.alert() 写入警告框 ####

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
        
    <script>
        window.alert("hello js");//写入警告框
    </script>
    </body>
    </html>

上面代码通过浏览器打开，我们可以看到如下图弹框效果  
**运行结果**![在这里插入图片描述][fe00a67912ba418bb659ef04234ebebf.png]

#### **使用 document.write() 写入 HTML 网页输出** ####

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
        
    <script>
        document.write("hello js");//写入html页面
    </script>
    </body>
    </html>

**运行结果**  
![在这里插入图片描述][933c4926558f41e6abe30b2e1152ee25.png]

#### **使用 console.log() 写入浏览器控制台** ####

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
    
    <script>
        console.log("hello js");//写入浏览器的控制台
    </script>
    </body>
    </html>

**运行结果**  
![在这里插入图片描述][30a4361915e74343a01111a8a061499f.png]

[JavaScript]: https://blog.csdn.net/qq_51447496/article/details/128085137
[JavaScript 1]: https://blog.csdn.net/qq_51447496/article/details/128085348
[JavaScript 2]: https://blog.csdn.net/qq_51447496/article/details/128086148
[JavaScript 3]: https://blog.csdn.net/qq_51447496/article/details/128086681
[JavaScript 4]: https://blog.csdn.net/qq_51447496/article/details/128088817
[JavaScript 5]: https://blog.csdn.net/qq_51447496/article/details/128087248
[JavaScript 6]: https://blog.csdn.net/qq_51447496/article/details/128088986
[Array_JavaScript]: https://blog.csdn.net/qq_51447496/article/details/128089474
[String_JavaScript]: https://blog.csdn.net/qq_51447496/article/details/128089631
[JavaScript 7]: https://blog.csdn.net/qq_51447496/article/details/128089766
[JavaScript_BOM]: https://editor.csdn.net/md/?articleId=128095193
[Window]: https://blog.csdn.net/qq_51447496/article/details/128095300
[confirm_setInterval_setTimeout]: https://blog.csdn.net/qq_51447496/article/details/128103458
[History_Location]: https://blog.csdn.net/qq_51447496/article/details/128104240
[Link 1]: https://blog.csdn.net/qq_51447496/article/details/128095524
[JavaScript_DOM]: https://blog.csdn.net/qq_51447496/article/details/128104720
[onclick_onfocus_onblur]: https://blog.csdn.net/qq_51447496/article/details/128110532
[onmouseout_onmouseover_]: https://blog.csdn.net/qq_51447496/article/details/128112439
[onsubmit_]: https://blog.csdn.net/qq_51447496/article/details/128112553
[Link 2]: https://blog.csdn.net/qq_51447496/article/details/128112770
[fe00a67912ba418bb659ef04234ebebf.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/c8c756cbca784bde8c52c8ff3662b9d1.png
[933c4926558f41e6abe30b2e1152ee25.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/48325ad3137d4689a74c5e5c50060d49.png
[30a4361915e74343a01111a8a061499f.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/f852a1cfd3b24b04b97329e52eaa0edb.png