我的JavaScript验证功能似乎不起作用。相同的验证格式似乎也不适用于我的其他输入，例如。姓。但是，它确实适用于我的电子邮件输入。我正在创建一个网页，在完整的代码中，我有这个JavaScript函数来验证名字，以便在提交时该字段不为空。
function validateFName() {
var firstname = document.getElementById('firstname').value;
if( firstname==null || firstname=="")
{
alert("Please input a first name");
}
}
此外，下面是正文中的输入代码：
<label> First Name: </label> <input type="text" name="firstname" maxlength="30" placeholder="John" /> <br><br>
以下是函数的调用：
<input type="submit" onclick="validateEmail(); validateFName(); validateLName(); validateGender(); validateDate(); validateVName(); validateVEmail();" /> <br>
以下是我的完整代码。 （尚未完成）
<!DOCTYPE html>
<html>
<head>
<title> Truth or Dare </title>
<style type='text/css'>
body {
font: 15px 'Lucida Grande', Verdana, sans-serif;
color: #404040;
background: purple;
}
nav {
width: 360px;
height: 70px;
margin-left: auto;
margin-right: auto;
}
.fancyNav{
/* Affects the UL element */
overflow: hidden;
display: inline-block;
}
.fancyNav li{
/* Specifying a fallback color and we define CSS3 gradients for the major browsers: */
background-color: #f0f0f0;
background-image: -webkit-gradient(linear,left top, left bottom,from(#fefefe), color-stop(0.5,#f0f0f0), color-stop(0.51, #e6e6e6));
background-image: -moz-linear-gradient(#fefefe 0%, #f0f0f0 50%, #e6e6e6 51%);
background-image: -o-linear-gradient(#fefefe 0%, #f0f0f0 50%, #e6e6e6 51%);
background-image: -ms-linear-gradient(#fefefe 0%, #f0f0f0 50%, #e6e6e6 51%);
background-image: linear-gradient(#fefefe 0%, #f0f0f0 50%, #e6e6e6 51%);
border-right: 1px solid rgba(9, 9, 9, 0.125);
/* Adding a 1px inset highlight for a more polished efect: */
box-shadow: 1px -1px 0 rgba(255, 255, 255, 0.6) inset;
-moz-box-shadow: 1px -1px 0 rgba(255, 255, 255, 0.6) inset;
-webkit-box-shadow: 1px -1px 0 rgba(255, 255, 255, 0.6) inset;
position:relative;
float: left;
list-style: none;
}
.fancyNav li:after{
/* This creates a pseudo element inslide each LI */
content:'.';
text-indent:-9999px;
overflow:hidden;
position:absolute;
width:100%;
height:100%;
top:0;
left:0;
z-index:1;
opacity:0;
/* Gradients! */
background-image:-webkit-gradient(linear, left top, right top, from(rgba(168,168,168,0.5)),color-stop(0.5,rgba(168,168,168,0)), to(rgba(168,168,168,0.5)));
background-image:-moz-linear-gradient(left, rgba(168,168,168,0.5), rgba(168,168,168,0) 50%, rgba(168,168,168,0.5));
background-image:-o-linear-gradient(left, rgba(168,168,168,0.5), rgba(168,168,168,0) 50%, rgba(168,168,168,0.5));
background-image:-ms-linear-gradient(left, rgba(168,168,168,0.5), rgba(168,168,168,0) 50%, rgba(168,168,168,0.5));
background-image:linear-gradient(left, rgba(168,168,168,0.5), rgba(168,168,168,0) 50%, rgba(168,168,168,0.5));
/* Creating borders with box-shadow. Useful, as they don't affect the size of the element. */
box-shadow:-1px 0 0 #a3a3a3,-2px 0 0 #fff,1px 0 0 #a3a3a3,2px 0 0 #fff;
-moz-box-shadow:-1px 0 0 #a3a3a3,-2px 0 0 #fff,1px 0 0 #a3a3a3,2px 0 0 #fff;
-webkit-box-shadow:-1px 0 0 #a3a3a3,-2px 0 0 #fff,1px 0 0 #a3a3a3,2px 0 0 #fff;
/* This will create a smooth transition for the opacity property */
-moz-transition:0.25s all;
-webkit-transition:0.25s all;
-o-transition:0.25s all;
transition:0.25s all;
}
/* Treating the first LI and li:after elements separately */
.fancyNav li:first-child{
border-radius: 4px 0 0 4px;
}
.fancyNav li:first-child:after,
.fancyNav li.selected:first-child:after{
box-shadow:1px 0 0 #a3a3a3,2px 0 0 #fff;
-moz-box-shadow:1px 0 0 #a3a3a3,2px 0 0 #fff;
-webkit-box-shadow:1px 0 0 #a3a3a3,2px 0 0 #fff;
border-radius:4px 0 0 4px;
}
.fancyNav li:last-child{
border-radius: 0 4px 4px 0;
}
/* Treating the last LI and li:after elements separately */
.fancyNav li:last-child:after,
.fancyNav li.selected:last-child:after{
box-shadow:-1px 0 0 #a3a3a3,-2px 0 0 #fff;
-moz-box-shadow:-1px 0 0 #a3a3a3,-2px 0 0 #fff;
-webkit-box-shadow:-1px 0 0 #a3a3a3,-2px 0 0 #fff;
border-radius:0 4px 4px 0;
}
.fancyNav li:hover:after,
.fancyNav li.selected:after,
.fancyNav li:target:after{
/* This property triggers the CSS3 transition */
opacity:1;
}
.fancyNav:hover li.selected:after,
.fancyNav:hover li:target:after{
/* Hides the targeted li when we are hovering on the UL */
opacity:0;
}
.fancyNav li.selected:hover:after,
.fancyNav li:target:hover:after{
opacity:1 !important;
}
/* Styling the anchor elements */
.fancyNav li a{
color: #5d5d5d;
display: inline-block;
font: 20px/1 Lobster,Arial,sans-serif;
padding: 12px 35px 14px;
position: relative;
text-shadow: 1px 1px 0 rgba(255, 255, 255, 0.6);
z-index:2;
text-decoration:none !important;
white-space:nowrap;
}
.fancyNav a.homeIcon{
background:url('home.png') no-repeat center center;
display: block;
overflow: hidden;
padding-left: 12px;
padding-right: 12px;
text-indent: -9999px;
width: 16px;
}
h2{
color: blue;
font-size: 20px;
}
input {
padding: 5px;
font-size: 15px;
text-shadow: 0px 1px 0px #fff;
outline: none;
-webkit-border-radius: 3px;
-moz-border-radius: 3px;
border-radius: 3px;
border: 1px solid #ccc;
-webkit-transition: .3s ease-in-out;
-moz-transition: .3s ease-in-out;
-o-transition: .3s ease-in-out;
}
input:focus {
border: 1px solid #fafafa;
-webkit-box-shadow: 0px 0px 6px #007eff;
-moz-box-shadow: 0px 0px 5px #007eff;
box-shadow: 0px 0px 5px #007eff;
}
label{
margin: 0;
padding: 0;
border: 0;
font-size: 100%;
font: inherit;
vertical-align: baseline;
}
#box {
width: 430px; margin: 60px auto; padding: 60px 30px;
background: white; border: 1px solid #e1e1e1;
-moz-box-shadow: 0px 0px 8px #444;
-webkit-box-shadow: 0px 0px 8px #444;
}
h1 {
font-size: 20px;
color: #445668;
text-transform: uppercase;
text-align: center;
margin: 0 0 35px 0;
text-shadow: 0px 1px 0px #f2f2f2;
}
</style>
<script type='text/javascript'>
function validateEmail() {
var email = document.getElementById('email').value;
if( email==null || email=="")
{
alert("Please input an email address");
}
}
function validateFName() {
var firstname = document.getElementById('firstname').value;
if( firstname==null || firstname=="")
{
alert("Please input a first name");
}
}
function validateLName() {
var lastname = document.getElementById('lastname').value;
if( lastname==null || lastname=="")
{
alert("Please input a last name");
}
}
function validateGender() {
var gender = document.getElementById('gender').value;
if( gender==null || gender=="")
{
alert("Please select a gender");
}
}
function validateDate() {
var date = document.getElementById('date').value;
if( date==null || date=="")
{
alert("Please select a date");
}
}
function validateVName() {
var vname = document.getElementById('vname').value;
if( vname==null || vname=="")
{
alert("Please input a victim's name");
}
}
function validateVEmail() {
var vemail = document.getElementById('vemail').value;
if( vemail==null || vemail=="")
{
alert("Please input a victim's email");
}
}
</script>
</head>
<body>
<div id="navi">
<nav>
<ul class="fancyNav">
<li id="home"><a href="#home" class="homeIcon">Home</a></li>
<li id="news"><a href="#truth">TRUTH</a></li>
<li id="about"><a href="#Dare">DARE</a></li>
</ul>
</nav>
</div>
<div id="box">
<form id="truth">
<h1> Truth </h1>
<label> First Name: </label> <input type="text" name="firstname" maxlength="30" placeholder="John" /> <br><br>
<label> Last Name: </label> <input type="text" name="lastname" maxlength="30" placeholder="Doe" /> <br><br>
<label> Email:</label> <input type="text" id="email" /> <br><br>
<label> Male </label><input type="radio" name="gender" value="male"/>
<label> Female </label><input type="radio" name="gender" value="female"/> <br><br>
<label> Date to be performed: </label><input type="date" name="date"/><br><br>
<h2> Victim </h2>
<label> Name: </label> <input type="text" name="vname" maxlength="30" /><br><br>
<label> Email:</label> <input type="text" id="vemail" /> <br><br>
<h2> Please select a truth questions below </h2> <br>
<input type="radio" name="truth" value="q1"> Have you ever fallen and landed on your head? <br>
<input type="radio" name="truth" value="q2"> Have you ever return too much change? <br>
<input type="radio" name="truth" value="q3"> Have you ever been admitted into the hospital? <br>
<input type="radio" name="truth" value="q4"> Have you ever baked a cake? <br>
<input type="radio" name="truth" value="q5"> Have you ever cheated on test? <br>
<input type="radio" name="truth" value="q6"> Did you ever wish you were never born? <br>
<input type="radio" name="truth" value="q7"> Did you ever hide from Sunday School? <br><br>
<input type="submit" onclick="validateEmail(); validateFName(); validateLName(); validateGender(); validateDate(); validateVName(); validateVEmail();" /> <br>
</form>
</div>
</body>
</html>
答案 0 :(得分：3)
当你说document.getElementById（“firstname”）时，你的html标签应该是这样的：
input type="text" id="firstname" name="firstname"
你忘了给元素赋予“id”属性。发布/提交表单时，“name”属性将用于获取服务器端的值。
答案 1 :(得分：0)
您尚未向您的元素提供ID输入要么提供ID，要么将方法更改为
的getElementsByTagName（＆＃34;的firstName＆＃34）;
答案 2 :(得分：0)
添加 id="firstname" 以完美地完成工作，因为这在输入字段中不存在，因此无法找到 getElementById('firstname') 找不到此元素，< / p>
<label> First Name: </label> <input type="text" name="firstname" maxlength="30" placeholder="John" id="firstname"/>
答案 3 :(得分：0)
可以肯定的是，养成在输入中添加姓名和ID的习惯
<input type='text' id='firstName' name='firstName'>
答案 4 :(得分：0)
由于您专门标记了html5 validation并根据您的Javascript代码中的验证要求，我认为使用HTML 5表单验证功能对您来说更合适。因此，减少了Javascript编码的工作量。
<!DOCTYPE html>
<html>
<head>
<title>Truth or Dare</title>
<style type='text/css'>
body {
font: 15px'Lucida Grande', Verdana, sans-serif;
color: #404040;
background: purple;
}
nav {
width: 360px;
height: 70px;
margin-left: auto;
margin-right: auto;
}
.fancyNav {
/* Affects the UL element */
overflow: hidden;
display: inline-block;
}
.fancyNav li {
/* Specifying a fallback color and we define CSS3 gradients for the major browsers: */
background-color: #f0f0f0;
background-image: -webkit-gradient(linear, left top, left bottom, from(#fefefe), color-stop(0.5, #f0f0f0), color-stop(0.51, #e6e6e6));
background-image: -moz-linear-gradient(#fefefe 0%, #f0f0f0 50%, #e6e6e6 51%);
background-image: -o-linear-gradient(#fefefe 0%, #f0f0f0 50%, #e6e6e6 51%);
background-image: -ms-linear-gradient(#fefefe 0%, #f0f0f0 50%, #e6e6e6 51%);
background-image: linear-gradient(#fefefe 0%, #f0f0f0 50%, #e6e6e6 51%);
border-right: 1px solid rgba(9, 9, 9, 0.125);
/* Adding a 1px inset highlight for a more polished efect: */
box-shadow: 1px -1px 0 rgba(255, 255, 255, 0.6) inset;
-moz-box-shadow: 1px -1px 0 rgba(255, 255, 255, 0.6) inset;
-webkit-box-shadow: 1px -1px 0 rgba(255, 255, 255, 0.6) inset;
position: relative;
float: left;
list-style: none;
}
.fancyNav li:after {
/* This creates a pseudo element inslide each LI */
content: '.';
text-indent: -9999px;
overflow: hidden;
position: absolute;
width: 100%;
height: 100%;
top: 0;
left: 0;
z-index: 1;
opacity: 0;
/* Gradients! */
background-image: -webkit-gradient(linear, left top, right top, from(rgba(168, 168, 168, 0.5)), color-stop(0.5, rgba(168, 168, 168, 0)), to(rgba(168, 168, 168, 0.5)));
background-image: -moz-linear-gradient(left, rgba(168, 168, 168, 0.5), rgba(168, 168, 168, 0) 50%, rgba(168, 168, 168, 0.5));
background-image: -o-linear-gradient(left, rgba(168, 168, 168, 0.5), rgba(168, 168, 168, 0) 50%, rgba(168, 168, 168, 0.5));
background-image: -ms-linear-gradient(left, rgba(168, 168, 168, 0.5), rgba(168, 168, 168, 0) 50%, rgba(168, 168, 168, 0.5));
background-image: linear-gradient(left, rgba(168, 168, 168, 0.5), rgba(168, 168, 168, 0) 50%, rgba(168, 168, 168, 0.5));
/* Creating borders with box-shadow. Useful, as they don't affect the size of the element. */
box-shadow: -1px 0 0 #a3a3a3, -2px 0 0 #fff, 1px 0 0 #a3a3a3, 2px 0 0 #fff;
-moz-box-shadow: -1px 0 0 #a3a3a3, -2px 0 0 #fff, 1px 0 0 #a3a3a3, 2px 0 0 #fff;
-webkit-box-shadow: -1px 0 0 #a3a3a3, -2px 0 0 #fff, 1px 0 0 #a3a3a3, 2px 0 0 #fff;
/* This will create a smooth transition for the opacity property */
-moz-transition: 0.25s all;
-webkit-transition: 0.25s all;
-o-transition: 0.25s all;
transition: 0.25s all;
}
/* Treating the first LI and li:after elements separately */
.fancyNav li:first-child {
border-radius: 4px 0 0 4px;
}
.fancyNav li:first-child:after,
.fancyNav li.selected:first-child:after {
box-shadow: 1px 0 0 #a3a3a3, 2px 0 0 #fff;
-moz-box-shadow: 1px 0 0 #a3a3a3, 2px 0 0 #fff;
-webkit-box-shadow: 1px 0 0 #a3a3a3, 2px 0 0 #fff;
border-radius: 4px 0 0 4px;
}
.fancyNav li:last-child {
border-radius: 0 4px 4px 0;
}
/* Treating the last LI and li:after elements separately */
.fancyNav li:last-child:after,
.fancyNav li.selected:last-child:after {
box-shadow: -1px 0 0 #a3a3a3, -2px 0 0 #fff;
-moz-box-shadow: -1px 0 0 #a3a3a3, -2px 0 0 #fff;
-webkit-box-shadow: -1px 0 0 #a3a3a3, -2px 0 0 #fff;
border-radius: 0 4px 4px 0;
}
.fancyNav li:hover:after,
.fancyNav li.selected:after,
.fancyNav li:target:after {
/* This property triggers the CSS3 transition */
opacity: 1;
}
.fancyNav:hover li.selected:after,
.fancyNav:hover li:target:after {
/* Hides the targeted li when we are hovering on the UL */
opacity: 0;
}
.fancyNav li.selected:hover:after,
.fancyNav li:target:hover:after {
opacity: 1 !important;
}
/* Styling the anchor elements */
.fancyNav li a {
color: #5d5d5d;
display: inline-block;
font: 20px/1 Lobster, Arial, sans-serif;
padding: 12px 35px 14px;
position: relative;
text-shadow: 1px 1px 0 rgba(255, 255, 255, 0.6);
z-index: 2;
text-decoration: none !important;
white-space: nowrap;
}
.fancyNav a.homeIcon {
background: url('home.png') no-repeat center center;
display: block;
overflow: hidden;
padding-left: 12px;
padding-right: 12px;
text-indent: -9999px;
width: 16px;
}
h2 {
color: blue;
font-size: 20px;
}
input {
padding: 5px;
font-size: 15px;
text-shadow: 0px 1px 0px #fff;
outline: none;
-webkit-border-radius: 3px;
-moz-border-radius: 3px;
border-radius: 3px;
border: 1px solid #ccc;
-webkit-transition: .3s ease-in-out;
-moz-transition: .3s ease-in-out;
-o-transition: .3s ease-in-out;
}
input:focus {
border: 1px solid #fafafa;
-webkit-box-shadow: 0px 0px 6px #007eff;
-moz-box-shadow: 0px 0px 5px #007eff;
box-shadow: 0px 0px 5px #007eff;
}
label {
margin: 0;
padding: 0;
border: 0;
font-size: 100%;
font: inherit;
vertical-align: baseline;
}
#box {
width: 430px;
margin: 60px auto;
padding: 60px 30px;
background: white;
border: 1px solid #e1e1e1;
-moz-box-shadow: 0px 0px 8px #444;
-webkit-box-shadow: 0px 0px 8px #444;
}
h1 {
font-size: 20px;
color: #445668;
text-transform: uppercase;
text-align: center;
margin: 0 0 35px 0;
text-shadow: 0px 1px 0px #f2f2f2;
}
</style>
</head>
<body>
<div id="navi">
<nav>
<ul class="fancyNav">
<li id="home"><a href="#home" class="homeIcon">Home</a>
</li>
<li id="news"><a href="#truth">TRUTH</a>
</li>
<li id="about"><a href="#Dare">DARE</a>
</li>
</ul>
</nav>
</div>
<div id="box">
<form id="truth">
<h1> Truth </h1>
<label>First Name:</label>
<input type="text" nam e="firstname" maxlength="30" placeholder="John" required="required" />
<br>
<br>
<label>Last Name:</label>
<input type="text" name="lastname" maxlength="30" placeholder="Doe" required="required" />
<br>
<br>
<label>Email:</label>
<input type="email" id="email" required="required" />
<br>
<br>
<label>Male</label>
<input type="radio" name="gender" value="male" required="required" />
<label>Female</label>
<input type="radio" name="gender" value="female" required="required" />
<br>
<br>
<label>Date to be performed:</label>
<input type="date" name="date" required="required" />
<br>
<br>
<h2> Victim </h2>
<label>Name:</label>
<input type="text" name="vname" maxlength="30" required="required" />
<br>
<br>
<label>Email:</label>
<input type="email" id="vemail" required="required" />
<br>
<br>
<h2> Please select a truth questions below </h2>
<br>
<input type="radio" name="truth" value="q1">Have you ever fallen and landed on your head?
<br>
<input type="radio" name="truth" value="q2">Have you ever return too much change?
<br>
<input type="radio" name="truth" value="q3">Have you ever been admitted into the hospital?
<br>
<input type="radio" name="truth" value="q4">Have you ever baked a cake?
<br>
<input type="radio" name="truth" value="q5">Have you ever cheated on test?
<br>
<input type="radio" name="truth" value="q6">Did you ever wish you were never born?
<br>
<input type="radio" name="truth" value="q7">Did you ever hide from Sunday School?
<br>
<br>
<input type="submit" />
<br>
</form>
</div>
</body>
</html>