testing regular expressions javascript

Question

I have written a regular expression for the quantity and the maximum they can order is 500 for each (summer, autumn, winter). The expression is -

 var chkquantity = ^([1-9]?\d|[1-4]\d{2}|500)$/

I'm not sure if the test is correct -

if ((chkquantity.test(quantity)== false){
  alertmsg = alertmsg + "Please limit each magazine to 500 copies or less:" + "\n";
}

?

I'm not sure what you mean? sorry i'm a complete beginner and i am struggling :( — user2073133
– user2073133, Commented Feb 15, 2013 at 17:42
@user2073133 If quantity is a string that's really a number, you can just do something in javascript like parseInt(quantity) and then check if it's > 500 — lmortenson
– lmortenson, Commented Feb 15, 2013 at 17:45
I guess your expression should be /^([1-9]|[1-9][0-9]|[1-4][0-9][0-9]|500)$/. — georg
– georg, Commented Feb 15, 2013 at 18:04

Shmiddty · Accepted Answer · 2013-02-15 17:47:33Z

1

If you are dealing with numbers, deal with them as numbers.

if (Number(quantity) > 500) {
    alertmsg = alertmsg + "Please limit each magazine to 500 copies or less:" + "\n";
}

edited Feb 15, 2013 at 17:47

Shmiddty

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answered Feb 15, 2013 at 17:43

Torsten Walter

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1 Comment

Torsten Walter Over a year ago

It depends on your input String no? This is no validation of the input of course. But this was not the question.

Phil Bozak · Accepted Answer · 2013-02-15 17:48:00Z

1

Building off Torsten's answer, you will probably also want to validate that it is a number.

if(Number(quantity) > 500 || isNaN(quantity)) {

answered Feb 15, 2013 at 17:48

Phil Bozak

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Comments

jagzviruz · Accepted Answer · 2013-02-15 17:56:14Z

0

Since you are dealing with numbers, you can get away by using simpler approach. Just validate that it is all digits, and the numeric value is less than or equal to 500

function checkLimit(val){
    if (!isNaN(val) && parseInt(val)<500)
        return true;
    else if(isNaN(val)){
        alert ("Enter valid quantity.");

    return false;
}

if (!checkLimit(quantity))
    alertmsg = alertmsg + "Please limit each magazine to 500 copies or less:" + "\n";

answered Feb 15, 2013 at 17:56

jagzviruz

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