DOM basic tutorial: Using DOM to set text boxes_Basic knowledge

1. Control the number of characters entered by the user

For single-line text boxes and password input boxes, you can use the maxlength attribute to control the number of characters entered by the user.
For multi-line text, maxlength is a custom attribute whose value is the maximum number of characters entered. When the onkeypress event occurs, the return value of the LessThan() function is returned. The function is as follows

Detailed code

Copy code The code is as follows:

Please enter your name:

I want to leave a message:

2. Set the mouse to automatically select text

The first is to automatically focus when the mouse passes over onmouseover = "this.focus"

The second is onfocus = "this.select()"
Code example:

Copy code The code is as follows:

For multiple code instances, you can use the following code to focus

Copy code The code is as follows:

           

               

                    请输入您的姓名:
                   
               

               

                    请输入您的密码: