Form Validation using Javascript inside PHP

Question

I have a simple problem but no matter what I try I can't see to get it to work. I have a form on a php page and I need to validate the qty value on my form so that it doesn't exceed $qty (value pulled from mySQL) and is not less than zero. Sounds easy--hmm wish it were..lol! I had it checking if the value was numeric and in my attempts to make this work I even broke that--not a good morning..lol!

Here's a snip of my JavaScript Fn:

<script type='text/javascript'>
    function checkQty(elem){
        var numericExpression = /^[0-9]+$/;
        if(elem.value.match(numericExpression)){
                return true;
            }else{
                alert("Quantity for RMA must be greater than zero and cannot be more than the original order!");
                elem.focus();
                return false;
        }
    }
    </script>

The function is called from the submit button, onClick:

<input type="submit" name="submit" onclick="checkQty(document.getElementById('qty')";">

I've tried:

var numericExpression = /^[0-9]+$/;
if(elem.value.match(numericExpression) || elem.value < 0 || elem.value > <? int($qty) ?>){

No dice....HELP!?!

Mikey how is this Java related? Why did you roll back the tag change? Is there something we all are not seeing? — Pekka
– Pekka, Commented Mar 26, 2010 at 13:11
It's not related--Gordon was offended I originally tagged javascript instead of java..lol! — Mikey1980
– Mikey1980, Commented Mar 26, 2010 at 13:18
@Mikey1980 He was not offended m8, its just like big big thing to misplace java with javascript or vice-versa, it would be like talking about car and thinking about carpet. — ant
– ant, Commented Mar 26, 2010 at 13:22
@Mikey1980 I wasn't offended. Java is just not an abbreviation for JavaScript. Java is a programming language very different to JavaScript. You should not say Java when you mean JavaScript. It's just plain wrong. — Gordon
– Gordon, Commented Mar 26, 2010 at 13:47

Neal Donnan · Accepted Answer · 2010-03-26 13:23:01Z

1

Maybe try and view the source of the page and check if the $qty value is be printed out.

Also I think you need to change the or (||) to an and (&&) based on the original if statement, otherwise it will skip the limit checks.

Also echo the variable to print it out.

i.e.

var numericExpression = /^[0-9]+$/;
if(elem.value.match(numericExpression) && elem.value < 0 && elem.value > <? echo $qty ?>){

edited Mar 26, 2010 at 13:23

answered Mar 26, 2010 at 13:16

Neal Donnan

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5 Comments

Adam Kiss Over a year ago

also, beware of shortened PHP open tag <? - it doesn't work everywhere.

Adam Kiss Over a year ago

shouldn't it be actually <?php echo $qty; ?>? I think it should.

Mikey1980 Over a year ago

I though it worked.. but now if the $qty and form qty are both 1 it throws the alert--I am so confused :s

Mikey1980 Over a year ago

@Neal - the && doesn't make sense to me, "If form value qty is not numeric OR is less than zero OR is greater-than db's qty then..."

Neal Donnan Over a year ago

@Mikey - based on the original if statement i.e. if you just added the limit checks into the if statement, it would need to be an and. i.e. if it's a number and greater than zero and less than qty return true, else error...

ant · Accepted Answer · 2010-03-26 13:16:39Z

0

Have you tried?

  <input type="submit" name="submit" onclick="return checkQty(document.getElementById('qty'));">

edited Mar 26, 2010 at 13:16

answered Mar 26, 2010 at 13:11

ant

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4 Comments

Will Morgan Over a year ago

I think you mean: <input type="submit" name="submit" onclick="return checkQty(document.getElementById('qty'));">

ant Over a year ago

@Will Morgan Yes a mistake which I didn't see, fixed now tnx

Mikey1980 Over a year ago

BINGO--That worked, but any idea how to to compare it to a PHP variable $qty?

ant Over a year ago

@Mikey1980 you're gonna have to ask seperate question for that

symcbean · Accepted Answer · 2010-03-26 13:33:02Z

0

You just need to make the PHP value available to the javascript e.g.

 <script type='text/javascript'>
 function checkQty(elem, max_value){
    if(parseInt(elem.value)>0
       && (parseInt(elem.value)<=max_value)){
            return true;
    }else{
            alert("Quantity for RMA must be greater than zero and less than original order!");
            elem.focus();
            return false;
    }
 }
 </script>
 ...
 <?php
     $max_value=(integer)method_of_fetching_max_value();
     print "<input type='submit' name='submit' 
             onclick='checkQty(document.getElementById(\"qty\", $max_value))'>  
     ";
 ?>

C.

answered Mar 26, 2010 at 13:33

symcbean

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2 Comments

Mikey1980 Over a year ago

WOW! I love that approach--however my HTML on this page is clean and mainly PHP free--easier for our designer, but will use this for other scripts going forward for sure! KUDOS!!

Mikey1980 Over a year ago

I tried your method and no dice... if $qty and form qty are both 1 it throws the error.

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