如果 javascript 验证失败，则聚焦文本字段
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focus textfield if javascript validation failed
提问by Mohammad Faisal
I've this code:
我有这个代码：
<html>
<head>
<script type="text/javascript">
function validate(){
var name=document.frm.name.value;
if(name.indexOf("A")==0){
alert(name);
}
}
</script>
</head>
<body>
<form name="frm" action="test.php">
Enter name:<input type="text" name="name" onblur="validate()"/>
Enter e-Mail:<input type="text" name="email" onblur=""/>
<input type="submit"/>
</form>
</body>
</html>
In above code, I'd tried to validate textfields when they lose focus. The script working fine if the name starts with A. But I want if the user enter different name which doesn't start with Ait will return the focus to the textfield name. For that I'd written this script:
在上面的代码中，我试图在失去焦点时验证文本字段。如果名称以A. 但我希望如果用户输入不同的名称，而不是以A它开头的将焦点返回到 textfield name。为此，我编写了这个脚本：
<script type="text/javascript">
var name = document.frm.name.value;
if(name.indexOf("A") == 0){
alert(name);
}else{
document.frm.name.focus();
}
</script>
then it doesn't works.
那么它不起作用。
Anybody could help with that what should I do to request focus of textfield name?
I've only a little knowledge of javascript.
任何人都可以提供帮助，我应该怎么做才能请求 textfield 的焦点name？
我对javascript.
回答by Teemu
Just give an idfor you form and refer it with document.getElementById('form_id'). Use of nameattribute in this context has been deprecated over a decade ago. Also namefor inputshould be something else than "name", rather use usernameor sth.
只需给id你一个表格并用document.getElementById('form_id'). name十多年前，在此上下文中使用属性已被弃用。也nameforinput应该是别的东西"name"，而不是 useusername或 sth。
HTML:
HTML:
<form id="frm" action="test.php">
Enter name:<input type="text" name="username" id="username" onblur="validate()"/>
Enter e-Mail:<input type="text" name="email" id="email" onblur=""/>
</form>
JavaScript:
JavaScript:
function validate(){
var form = document.getElementById('frm');
if (form.username.value.indexOf("A") === 0) {
alert(name);
} else {
form.username.focus();
}
}
Instead of retrieving the idof the form, you can also pass the formto validate()as an argument: onblur="validate(this);". Then use that argument as a formin the eventhandler:
相反检索的id的form，你也可以通过form以validate()作为参数：onblur="validate(this);"。然后将该参数用作form事件处理程序中的 a ：
function validate(form){
if (form.username.value.indexOf("A") === 0) {
alert(name);
} else {
form.username.focus();
}
}
EDIT
编辑
Focus doesn't seem to work without a delay, you can try this (the inputhas an id="username"):
焦点似乎没有延迟，你可以试试这个（input有一个id="username"）：
function focusTo (elm) {
elm.focus();
return;
}
function validate(){
var form = document.getElementById('frm');
if (form.username.value.indexOf("A") === 0) {
alert(name);
} else {
alert('error');
setTimeout(function () {focusTo(form.username);}, 10);
}
}
回答by 999k
modifiy your script like this
像这样修改你的脚本
<html>
<head>
<script type="text/javascript">
function validate(){
var name=document.frm.name.value;
if(name.indexOf("A")==0){
alert(name);
}
}
</script>
</head>
<body >
<form id="frm" action="test.php">
Enter name:<input type="text" name="username" onblur="validate()"/>
Enter e-Mail:<input type="text" name="email" onblur=""/>
<input type="submit" onclick="check()"/>
</form>
<SCRIPT LANGUAGE="JavaScript">
<!--
function validate()
{
var name = document.getElementById('frm').username.value;
if(name.indexOf("A") == 0){
alert(name);
document.getElementById('frm').email.focus();
}else{
document.getElementById('frm').username.focus();
}
}
function check()
{
var name = document.getElementById('frm').username.value;
if(name.indexOf("A") == 0){
}else{
alert("Please enter a name starting with 'A'");
document.getElementById('frm').username.focus();
}
}
//-->
</SCRIPT>
</body>
</html>
You want to execute function validate()on event onblur. in the script you have written the code for focusing, but not added it in a function.
您想validate()在 event上执行函数onblur。在脚本中，您编写了用于聚焦的代码，但未将其添加到函数中。
回答by Viks
try this document.frm.username.focus();. i hope it will work.
试试这个document.frm.username.focus();。我希望它会起作用。
