Regular Expressions

[KMarshall]

I've been trying to create a regular expression to validate a string, but since this is my first time with regular expressions, I'm making very hard work of it.

The accepted string format is NNNNAA where N=numberic and A=Alpha. The field is forced uppercase.

I can validate the NNNN part but can't work out how to also check the AA part.

Here's what I have so far:
<Sctipt Language="JavaScript">
function check(){
var rExp=/^\d{4}$/ //Allowed NNNNAA

if (document.myForm.inputField.value.search(rExp)==-1){ //if match failed
alert('Invalid')
}else{
alert('Ok')
}
}
</Script>

<form name="myForm" method="post">
<input type="text" name="inputField" value="" onBlur="check()" size="6" maxlength="6">
</form>



Can anyone offer any assistance.

Thanks.
Kevin.

 

[grtfercho]

var rExp=/^\d{4}[a-z][a-z]$/i <-- the "i" at the end makes the expression insensitive... a or A if you only want to accept uppercase then change the [a-z] to [A-Z] and get rid of the "i"

grtfercho çB^]\..
"Imagination is more important than Knowledge" A. Einstein
-----------------------------------------------

http://www.llajta.com

 

[grtfercho]

optionally
var rExp=/^\d{4}[a-z]{2}$/

grtfercho çB^]\..
"Imagination is more important than Knowledge" A. Einstein
-----------------------------------------------

http://www.llajta.com

 

[Cresby]

FWIW
dunno if it helps but IE5.5, NS 4.5 and Firefox all do things differently and what I found was that often somewhat like this helped

// get it into a variable first
var fred = document.myForm.inputField.value;
alert(fred)
// then use it
var bill =fred.search(rExp)
alert(bill)
if (bill==-1){etc;}

I found that testing for null before a search or substring was essential or it just stops and does nothing and doesn't tell you (sound familiar?)

ie
if (fred){ // true if not null
if (fred.search(rExp)==-1){
alert("so that's it!")
}
}

good luck.

http://cresby.com

OH never used it in real situations but there is the method

try{
fred = iffycode(fred)
}
catch
{
alert("this is wrong - fred = iffycode(fred)")
}

 

[KMarshall]

Thanks for the very fast reply guys!

I've gone with grtfercho's answer as it is the easiest one for me to understand although I do appreciate what Cresby is saying about the nulls.

I have one more thing to add to the mix. What if I need an optional character on the end? The last character can either be nothing or a 'Z'.

Is this possible?

The format is AAAANNZ

 

[KMarshall]

I got it: var rExp=/^\d{4}[a-z]{2,3}$/

 

[grtfercho]

Actually
var rExp=/^\d{4}[a-z]{2,3}$/

will catch 1234ABC and 1234AZ
from what I understand the last character can be present and if it is, it has to be a Z.
therefore this will give you better results

var rExp=/^\d{4}[a-z]{2}Z?$/


grtfercho çB^]\..
"Imagination is more important than Knowledge" A. Einstein
-----------------------------------------------

http://www.llajta.com

 

[KMarshall]

Brilliant, thanks grtfercho.
I was struggling with that very problem after my initial excitement. Thanks!

 

[spewn]

hey guys, have been reading this string...although old, maybe i'll get a response.

i'm using the following code:

function alphaCheck(x) {
alphaOnly='no';
 if (x!='') {
   for (c=0; c<x.length; c++) {
    if (x.substr(c,1).match(/[a-zA-Z]/) != null) {
    alphaOnly='yes';
    }
   }
 }
return alphaOnly;
}

it will catch the number if there is only numbers in the field...but as long as there is a alpha character in there somewhere, it doesn't throw a red flag.

my goal is to search and confirm the value is all alpha only, no symbols, no numbers, etc.

any ideas is appreciated.

- g

 

[tsuji]

Question answered in the original thread:

http://tek-tips.com/viewthread.cfm?qid=1033755&page=1

Please avoid prolifering same question to multiple threads. In particular you get adequate attention in the original as op.