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我刚开始学习HTML和JavaScript。 我想验证一个HTML表单的空字段，并使用for循环打印相应的错误消息作为输出。无法使用JavaScript打印for循环的验证错误
下面是jsp页面和javascript代码。
<script>
var err = new Array();
var i = 0,
flag = 0;
function validateForm() {
var x = document.forms["RegistrationController"]["firstname"].value;
if (x == null || x == "") {
err[i++] = "First name cannot be empty";
flag = 1;
}
var a = document.forms["RegistrationController"]["dob"].value;
if (a == null || a == "") {
err[i++] = "Date of birth cannot be empty";
flag = 1;
}
var b = document.forms["RegistrationController"]["address_line_1"].value;
if (b == null || b == "") {
err[i++] = "Address cannot be empty";
flag = 1;
}
var c = document.forms["RegistrationController"]["city"].value;
if (c == null || c == "") {
err[i++] = "city cannot be empty";
flag = 1;
}
var d = document.forms["RegistrationController"]["pincode"].value;
if (d == null || d == "") {
err[i++] = "pincode cannot be empty";
flag = 1;
}
var e = document.forms["RegistrationController"]["mobile_no"].value;
if (e == null || e == "") {
err[i++] = "mobile no cannot be empty";
flag = 1;
}
var f = document.forms["RegistrationController"]["email"].value;
if (f == null || f == "") {
err[i++] = "email cannot be empty";
flag = 1;
}
if (flag == 1) {
var string = "";
for (j = 0; j < err.length; j++) {
document.getElementById("error").innerHTML = err[i];
return false;
}
}
} </script><html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Registration</title>
</head>
<body>
<div class="error" id="error"></div>
<h1>Registration Form</h1>
<div class="ex">
<form name="RegistrationController" method="post" onsubmit="return validateForm()">
<table style="with: 50%">
<tr>
<td>First name</td>
<td>
<input type="text" name="firstname" />
</td>
</tr>
<tr>
<td>Last name</td>
<td>
<input type="text" name="lastname" />
</td>
</tr>
<tr>
<td>Date of Birth</td>
<td>
<input type="text" name="dob" />
</td>
</tr>
<tr>
<td>Address Line 1</td>
<td>
<input type="text" name="address_line_1" />
</td>
</tr>
<tr>
<td>Address Line 2</td>
<td>
<input type="text" name="address_line_2" />
</td>
</tr>
<tr>
<td>state</td>
<td>
<input type="text" name="state" />
</td>
</tr>
<tr>
<td>city</td>
<td>
<input type="text" name="city" />
</td>
</tr>
<tr>
<td>pincode</td>
<td>
<input type="text" name="pincode" />
</td>
</tr>
<tr>
<td>Mobile no</td>
<td>
<input type="text" name="mobile_no" />
</td>
</tr>
<tr>
<td>email</td>
<td>
<input type="text" name="email" />
</td>
</tr>
<tr>
<td>gender</td>
<td>
<input type="radio" name="gender" />Male</td>
<td>
<input type="radio" name="gender" />Female</td>
</tr>
</table>
<input type="submit" value="register" />
</form>
</div>
</body>
</html>
'的innerHTML = + ERR [1] +“
”;'为'innerHTML'将取代'在每次迭代HTML' ... – Rayon
功能甚至没有定义的，因为你写的脚本标记，< script >代替
参考这个答案。我修改了一下你的代码。
<script>标签不应该包括空格之后<i是refered但您在使用
jfor循环我认为使用的getElementById是更有效的
来源
2016-04-29 05:42:15 Bhugy
当你使用'getElementById'，你必须定义输入id像这样'' –