启用和禁用javascript中的下载按钮

Question

我制作了一个表格，要求提供姓名和电子邮件以便下载文件。问题是，无论你是否填写了名称，"下载"按钮都会起作用，尽管它会显示一条消息，告知下载文件的信息丢失。

我没有足够的js知识，无法找到在输入姓名和电子邮件时让"下载"按钮工作的方法。

有人能帮忙吗？请

HTML下载按钮：

<button type="submit" onclick="window.location.href='download/CV.pdf'">Download</button>

JS:

var email = document.getElementById("email").value;
var error_message = document.getElementById("error_message");
error_message.style.padding = "10px";
var text;
if(name.length < 5){
text = "Please Enter valid Name";
error_message.innerHTML = text;
return false;
}
if(email.indexOf("@") == -1 || email.length < 6){
text = "Please Enter valid Email";
error_message.innerHTML = text;
return false;
}
alert("Thank you!");
return true;
}

谢谢！

Answer 1

您可以这样做。

<form onsubmit="return validateForm(event)">
<button type="submit">Download</button>
<input type="text" id="email" placeholder="Email">
<input type="text" id="name" placeholder="Name">
</form>
...
function validateForm(event) {
event.preventDefault();
var email = document.getElementById("email").value;
var name = document.getElementById("name").value;
var error_message = document.getElementById("error_message");
error_message.style.padding = "10px";
var text;
if(name.length < 5){
text = "Please Enter valid Name";
error_message.innerHTML = text;
return;
}
if(email.indexOf("@") == -1 || email.length < 6){
text = "Please Enter valid Email";
error_message.innerHTML = text;
return;
}
window.location.href = "download/CV.pdf";
}