JSFiddle - React, Tailwind, and code Playground

by gothic

HTML

<input type="text" id="address" value="请输入邮箱密码">
    <input type="text" id="passwod" value="请输入邮箱密码">
        <input type="button" value="登录">

JavaScript

$(function () {
 $ ("#address").focus(function() {
    var txt_value = $(this).val();
    if(txt_value=="请输入邮箱地址") {
    $(this).val("")
    }
});
$("#address").blur(function() {
var txt_value = $(this).value ();
    if(txt_value==""){
    $(this).val("请输入邮箱地址")
    }
});
})