why does this regex work outside of a javascript function but not inside of it?
Okay so I'm kind of new to regexps in general, let alone in Javascript.
I am trying to work on a form validation project and I found a site where they have a list of useful sample regexps for various things here which has a few for email validation, which is what I'm attempting at the moment. Anyway, following this example for form validation on w3schools I was able to get it working properly using their example and the regexp works outside of the javascript function, but for some reason when I call it inside the function it returns a value of undefined. Here's my code:<html>
<head>
<title>formzz validate-jons</title>
<script type="text/javascript">
pattern = new RegExp("^[0-9a-zA-Z]+@[0-9a-zA-z]+[\.]{1}[0-9a-zA-Z]+[\.]?[0-9a-zA-Z]+$");
function valid8email(field, txt)
{
with(field)
{
//at_pos = value.indexOf('@');
//dot_pos = value.lastIndexOf('.');
if(!pattern.test(value)) //at_pos < 1 || (dot_pos - at_pos) < 2)
{
alert(txt);
return false;
}
else
{
return true;
}
}
}
function valid8(form)
{
with(form)
{
if(valid8email(email, "you must enter an email address") == false)
{
email.focus();
return false;
}
}
}
</script>
</head>
<body>
<form action="#" me开发者_开发技巧thod="POST" onsubmit="return valid8(this)">
Email: <input type="text" name="email" size="30" />
<input type="submit" value="clicky-click" />
</form>
<script type="text/javascript">
alert(pattern.test(""));
</script>
</body>
</html>
Okay... so the alert in the script tags inside the body works just fine.
I've done numerous tests inside the javascript function itself and checked various things:
- the type of 'value' is String
- the function returns 'undefined' when called inside the javascript
- the regex itself works fine as it will return true when the proper formatting is entered in the script tags below
So what could the issue be? I am confused.
The problem is that pattern refers to field.pattern (an HTML5 attribute) because you're using it inside the with(), and that's a string, not your regex. If you called it something else like pattern1, it would work fine.
That being said, don't use with in the first place, and you won't have these issues :)
The non-with version looks like this:
var pattern = new RegExp("^[0-9a-zA-Z]+@[0-9a-zA-z]+[\.]{1}[0-9a-zA-Z]+[\.]?[0-9a-zA-Z]+$");
function valid8email(field, txt) {
if (!pattern.test(field.value))
{
alert(txt);
return false;
}
else {
return true;
}
}
function valid8(form) {
if (valid8email(form.email, "you must enter an email address") == false) {
form.email.focus();
return false;
}
}
You can test it out here.
加载中,请稍侯......
精彩评论