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numeric checker

 
 
Tom
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      01-08-2007
Being a newbie to JS, I would appreciate some advice. When a visitor
enters a number into a textbox, I want to check that it is 15 digits long
and then display a message accordingly and the following script does that
OK. However, I want also to make sure that only "numbers" are entered and
no other characters. Again the attached does this but is clumsy to say the
least! How do I get it to loop back to the input box if it contains a
non-numeric, before it goes off to check for 15 digits?
<script>
var ok = " This chip will work";
var nook = "This chip will not work";
function check_input()
{
var entry = document.forms.f.textfield.value;
var length = entry.length
document.clear();
res = isNaN(entry) ? "please enter only numbers": "Press OK to continue";
alert(res);
document.write("<body bgcolor=\"44eedd\">");
document.write("<body text=\"000000\">");
document.write("<B><font size=3 face='arial'>")
if(length == 15) document.write(ok);
else
document.write(nook);
}
</script>
Any help would be greatly appreciated.
Tom


 
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cwdjrxyz
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      01-08-2007

Tom wrote:
> Being a newbie to JS, I would appreciate some advice. When a visitor
> enters a number into a textbox, I want to check that it is 15 digits long
> and then display a message accordingly and the following script does that
> OK. However, I want also to make sure that only "numbers" are entered and
> no other characters. Again the attached does this but is clumsy to say the
> least! How do I get it to loop back to the input box if it contains a
> non-numeric, before it goes off to check for 15 digits?
> <script>
> var ok = " This chip will work";
> var nook = "This chip will not work";
> function check_input()
> {
> var entry = document.forms.f.textfield.value;
> var length = entry.length
> document.clear();
> res = isNaN(entry) ? "please enter only numbers": "Press OK to continue";
> alert(res);
> document.write("<body bgcolor=\"44eedd\">");
> document.write("<body text=\"000000\">");
> document.write("<B><font size=3 face='arial'>")
> if(length == 15) document.write(ok);
> else
> document.write(nook);
> }
> </script>


There are people here who use javascript, and some may answer you.
However I also suggest that you go to the Usenet group
comp.lang.javascript. They have an extensive FAQ that might be useful
to you and might help. You are quite right in wanting to check for
charcter length entered and checking for numbers only also, since there
are people who will enter nearly anything into a form, including hacker
scripts. Also server side script such as php sometimes can have
advantages, especially if some of your site visitors have javascript
turned off.

 
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Neredbojias
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Posts: n/a
 
      01-09-2007
To further the education of mankind, "Tom" <(E-Mail Removed)> vouchsafed:

> Being a newbie to JS, I would appreciate some advice. When a
> visitor enters a number into a textbox, I want to check that it is 15
> digits long and then display a message accordingly and the following
> script does that OK. However, I want also to make sure that only
> "numbers" are entered and no other characters. Again the attached
> does this but is clumsy to say the least! How do I get it to loop
> back to the input box if it contains a non-numeric, before it goes off
> to check for 15 digits?

(snip)
> Any help would be greatly appreciated.
> Tom


The easiest way is a regular expression match check for 15 numeric digits.

OTTOMH: var.match(/\d\d\\d\d\d\d\d\d\d\d\d\d\d\d\d/);

or

var.match(/\d{15}/);

--
Neredbojias
Infinity has its limits.
 
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Toby Inkster
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      01-09-2007
Tom wrote:

> document.write("<body bgcolor=\"44eedd\">");
> document.write("<body text=\"000000\">");
> document.write("<B><font size=3 face='arial'>")


What in the name of sweet Jesus is that?!

You're trying to output not one but two *extra* BODY elements. An HTML
document must contain precisely *one* BODY element. The FONT element is
deprecated too, though that's the least of your worries.

Better:

<script type="text/javascript">
var ok = "This chip will work";
var nook = "This chip will not work";

function check_input()
{
var entry = document.forms.f.textfield.value;
window.alert(empty.match(/\d{15}/) ? ok : nook);
}
</script>

--
Toby A Inkster BSc (Hons) ARCS
Contact Me ~ http://tobyinkster.co.uk/contact

 
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