The input prompt word disappears when the focus disappears or the input changes.

I. When the focus is obtained, the prompt word disappears.
< input type = "text" name = "textfield" value = "Here is the prompt content" onclick = "if(value==defaultValue){value=‘‘;this.style.color=‘#000‘}" onBlur = "if(!value){value=defaultValue;this.style.color=‘#999‘}" />  Ii. When modifying textThe prompt word disappears (but the placeholder has compatibility issues) < input class = "text" type = "email" name = "email" spellcheck = "false" placeholder = "Mailbox" autofocus > < input class = "text" type = "password" name = "password" placeholder = "Password" > < input class = "button" type = "submit" value = "Login" >