您好，我正在尝试获取此代码来验证文本框，以便它们必须包含一个值；如果他们不这样做，我希望出现一条消息，解释这些字段不能为空。这是我编写的代码:
<head>
<title>Exam entry</title>
<script language="javascript" type="text/javascript">
function validateForm() {
var result = true;
var msg="";
if (document.ExamEntry.name.value=="") {
msg+="You must enter your name \n";
document.ExamEntry.name.focus();
document.gotElementById('name').style.color="red";
result = false;
}
if (document.ExamEntry.subject.value=="") {
msg+="You must enter the subject \n";
document.ExamEntry.subject.focus();
document.gotElementById('subject').style.color="red";
result = false;
}
if (document.ExamEntry.examno.value=="") {
msg+="You must enter an examination number \n";
document.ExamEntry.examno.focus();
document.gotElementById('examno').style.color="red";
result = false;
if(msg==""){
return result;
}
{
alert(msg)
return result;
}
}
</script>
</head>
<body>
<h1>Exam Entry Form</h1>
<form name="ExamEntry" method="post" action="success.html">
<table width="50%" border="0">
<tr>
<td id="name">Name</td>
<td><input type="text" name="name" /></td>
</tr>
<tr>
<td id="subject">Subject</td>
<td><input type="text" name="subject" /></td>
</tr>
<tr>
<td id="examno">Examination Number</td>
<td><input type="integer" name="examno" /></td>
</tr>
<tr>
<td><input type="submit" name="Submit" value="Submit" onclick="return validationFrom();" /></td>
<td><input type="reset" name="Reset" value="Reset" /></td>
</tr>
</table>
</form>
</body>
任何帮助都会非常感谢
最佳答案
- getElementById 而不是 getelementById
- 使用 fullName 代替保留字名称
- 不要使用与表单名称相同的 ID - IE 会混淆
- 不要使用提交按钮的onclick。而是使用表单 onsubmit
- 您可能不被允许 POST 到 HTML 文件
- HTML5 支持 type="number"而不是 "integer"
- 将属性
value添加到每个字段
这是我的建议 - DEMO
我已更改标签 ID 并将名称更改为 fullName
function setError(fld,id,msg) {
if (fld.value=="") {
document.getElementById(id).className="error";
return msg;
}
document.getElementById(id).className="normal";
return "";
}
window.onload=function() {
document.getElementById("ExamEntry").onsubmit=function() {
var msg,msgs=[],focusField="";
msg=setError(this.fullName,"fullNameLabel","You must enter your name");
if (msg) { msgs.push(msg); focusField = this.fullName;}
msg=setError(this.subject,"subjectLabel","You must enter the subject");
if (msg) { msgs.push(msg); focusField = focusField || this.subject;}
var examno = this.examno;
msg = setError(examno,"examnoLabel","You must enter an examination number");
if (msg) { msgs.push(msg); focusField = focusField || examno;}
else {
if (isNaN( examno.value) || examno.value.length<4) {
msgs.push("You must enter a valid examination number");
document.getElementById("examnoLabel").className="error"
focusField = focusField || this.examno;
}
}
if(focusField) {
alert(msgs.join("\n"));
focusField.focus();
return false;
}
return true; // allow submission
}
}
关于javascript - 验证文本框，以便必须输入值，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14376882/