Question

function check_empty() {
if (document.getElementById('CompanyName').value == "" || document.getElementById('ContactName').value == "" || document.getElementById('Address').value == "" || document.getElementById('PhoneNumber').value == "" || document.getElementById('Email').value == ""){
alert("Fill All Fields !");
} else {
/*want to add a class="my" */
alert("Form Submitted Successfully...");
}
}

/*html code*/
<a href="javascript:%20check_empty()" class="my">Submit to download</a>

当我点击链接＆＃34;提交下载＆＃34; ＆＃34; check_empty（）＆＃34;被叫，如果所有的filds都是空的，它会询问＆＃34;填写所有字段！＆＃34;否则我想打电话给一个班级＆＃34;我的＆＃34;，现在是html的元素。如何在js上添加它？

Answer 1

<强>更新

我认为你在寻找的是如何使用attr placeholder，required和autofocus你不需要javascript来检查输入是否为空尝试这样：< / p>

＆＃13;

<form>
    <input id=CompanyName type=text placeholder=CompanyName required autofocus />
    <input id=ContactName type=text placeholder=ContactName required />
    <input id=Address type=text placeholder=Address required />
    <input id=PhoneNumber type=text placeholder=PhoneNumber required />
    <input id=Email type=text placeholder=Email required />
    <input type=submit value=send />
</form>

＆＃13;

现在，您可以在表单准备就绪时执行某些操作

＆＃13;

function sendMyForm(event){
    alert("Form Submitted Successfully...");
}

var sendForm = document.querySelector("form");

sendForm.addEventListener("submit", sendMyForm, false);

＆＃13;

<form>
    <input id=CompanyName type=text placeholder=CompanyName required autofocus />
    <input id=ContactName type=text placeholder=ContactName required />
    <input id=Address type=text placeholder=Address required />
    <input id=PhoneNumber type=text placeholder=PhoneNumber required />
    <input id=Email type=text placeholder=Email required />
    <input type=submit value=send />
</form>

＆＃13;

使用classList

 document.querySelector("#CompanyName").classList.add('my');

所以你的代码看起来像这样

function check_empty() {
   if (document.getElementById('CompanyName').value == "" || document.getElementById('ContactName').value == "" || document.getElementById('Address').value == "" || document.getElementById('PhoneNumber').value == "" || document.getElementById('Email').value == ""){
      alert("Fill All Fields !");
   } else {
      /*want to add a class="my" */
      document.querySelector("#CompanyName").classList.add('my');
      /*document.getElementById("CompanyName").classList.add('my')*/
      alert("Form Submitted Successfully...");
   }
}

Answer 2

您是否询问如何通过单击::

调用两个javascript函数

如果是这样的话......试试这个......

<a href="javascript:void()" onClick="return check_empty() ? my() : false"> Submit to download </a>

如何在js上的else条件中添加一个类

2 个答案: