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i want to write that a javascript function that allows only numbers,* and ?.
Maciej Los 16-May-13 2:52am
Have you tried something?

The regex is simple:
Mohibur Rashid 16-May-13 3:10am
i need to learn regex :)
OriginalGriff 16-May-13 3:23am
Get a copy of Expresso

Iit's free, and it examines and generates Regular expressions.
Mohibur Rashid 16-May-13 3:29am
thanks, sure will do
Arjun Menon U.K 20-May-13 1:58am
Hi, i have a doubt. i want to check a textbox value with regex that allow only a-z,A-Z,0-9.. i came across a regex ^[a-zA-Z0-9]+$ and ^[a-zA-Z0-9]*$
I would like to know what the +$ and *$ means. The ^ denotes starting of the string being checked rt? . Please correct if i am wrong
OriginalGriff 20-May-13 2:23am
+ means "one or more"
* means "zero or more"
^ means "start of string"
$ means "end of string"

Get a copy of Expresso - it explains this and helps a lot - the link is just above!
Arjun Menon U.K 20-May-13 4:14am
thanks griff
Arjun Menon U.K 20-May-13 4:16am
sadly its blocked by my company's firewall.. I want to check a value entered contains only numbers and characters from a-f. like hexadecial number,can i check like this ^[a-fA-F0-9]*$
OriginalGriff 20-May-13 4:38am
You might want to use a '+' instead of a '*', as that will match an empty field as well.
Arjun Menon U.K 20-May-13 4:18am
one more thing. If by giving the regEx exp as above does the test method check the order too. like whether the inputted value starts with characters then numbers.. ???
OriginalGriff 20-May-13 4:40am
If you want characters-then-numbers you need a different regex such as:
Which expects one or more uppercase alpha followed by zero or more digits
There is several key event that can be handled for user input controlling.

for simplification I will only talk about onkeypress

to process a user input you must have to return true or false.

as example

<input type=text onkeypress='return false;'> <!-- this will discard whatever the user types-->
<input type=text onkeypress='return false;'> <!-- this will allow whatever the user types-->

try this on browser.

say you want to allow only 0 and 1. the simple example would be

function test(e){
 var e=window.event || e
 return e.charCode==48 || e.charCode==49 ? true:false;

<input type=text onkeypress='return test(event);'> <!--only let you print 0 or 1 -->

hope it will guide you a little

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