Need help with RegExp

**codybonvo** · 03-18-2011 10:39 AM

I need to validate that the the user has entered a ten digit number into the text box, and need some help with the code.
Here is what I have:

<html>
<head>
<title>Checking with RegExp</title>
</head>
<body>
<script type="text/javascript">
function checknumber() {
var tendigitnum = document.getElementById("text").value;
var check=/^\d{10}$/;
if (check.test(tendigitnum)) {
window.alert("You entered"+tendigitnum);
}
else {
window.alert("Please enter a valid 10 digit number");
}
</script>
<form method="post" name="submitnumber" onsubmit="checknumber()">
<input type="text" id="text" name="inputnumber" size="15"></input>
<input name="check" value="Check" type="submit"></input>
</body>
</html>

**WolfShade** · 03-18-2011 11:16 AM

The regex is formatted properly, it looks like; you want to make sure that the whole string is nothing but 10 digits.

You are trying to compare the value of an element that does not exist. You don't have an element named "text", you have a text input named "inputnumber". So:

Code:

function checknumber() {
var tendigitnum = document.getElementById("inputnumber").value;
var check=/^\d{10}$/;
if (check.test(tendigitnum)) {
window.alert("You entered"+tendigitnum);
}
else {
window.alert("Please enter a valid 10 digit number");
}

Always be on the look out for JS error messages.. they can tell you much about what the issue is.

Also, you can remove "window." from before alert; you don't need it.

**codybonvo** · 03-18-2011 03:23 PM

The page should display an alert box telling whether the number was ok or not at the end. It still doesn't
here is the code:

<html>
<head>
<title>Checking with RegExp</title>
</head>
<body>
<script type="text/javascript">
function checknumber() {
var tendigitnum = document.getElementById("inputnumber").value;
var check=/^\d{10}$/;
if (check.test(tendigitnum)) {
window.alert("You entered"+tendigitnum);
}
else {
window.alert("Please enter a valid 10 digit number");
}
</script>
<form method="post" name="submitnumber" onsubmit="checknumber()">
<input type="text" id="text" name="inputnumber" size="15"></input>
<input name="check" value="Check" type="submit"></input>
</body>
</html>

**WolfShade** · 03-18-2011 03:39 PM

Everything looks correct, except for the "window.alert" parts. Change those to just "alert". If that doesn't fix it, let me know. I'll take a closer look, in the meantime.

I just noticed - you are not doing anything to prevent the form from being submit. Set your onsubmit to "return checknumber();", then:

Code:

alert("You entered"+tendigitnum);
return true;

.. and ..

Code:

alert("Please enter a valid 10 digit number");
return false;

**codybonvo** · 03-18-2011 04:03 PM

here is my new code, and it is still not working. Please help
thanks

<html>
<head>
<title>Checking with RegExp</title>
</head>
<body>
<script type="text/javascript">
function checknumber() {
var tendigitnum = document.getElementById("inputnumber").value;
var check=/^\d{10}$/;
if (check.test(tendigitnum)) {
window.alert("You entered"+tendigitnum);
}
else {
window.alert("Please enter a valid 10 digit number");
}
</script>
<form method="post" name="submitnumber" onsubmit="checknumber()">
<input type="text" id="text" name="inputnumber" size="15"></input>
<input name="check" value="Check" type="submit"></input>
</body>
</html>

**clueful** · 03-18-2011 04:06 PM

Originally Posted by codybonvo

here is my new code, and it is still not working. Please help

Please help yourself and stop ignoring the error console.

**codybonvo** · 03-18-2011 04:17 PM

Ok, I got it to work with some more work.
Thank you for the help

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Need help with RegExp

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