Question

I’ve run into a problem in my validation script to check the Australian postcodes.
It doesn’t seem to be incrementing through the multi-dimension array which contains the postcode values.

Here’s the function:

function validateAustralia(postcode, ranges) {

           for (var i = 0; i < ranges.length; i++) {
                     console.log(i);
//returns only 0, when it should return 0, 1, 2.
                     console.log("postcode: " + postcode + " " + "ranges: " + ranges);
//returns postcode: 2000 ranges: 200,299,2600,2618,2900,2920
                     console.log("ranges - low: " + ranges[2][0] + " " + "ranges - high: " + ranges[2][1]);
                     //returns ranges - low: 2900 ranges - high: 2920
                if (postcode >= ranges[i][0] && (postcode <= ranges[i][1])) {
                     valid = true;
                     //confirmation();
                     //break;
                } else {
                     inelegible();
                     return false;
                }
           }
     }

For New South Wales, for example

ranges = [ [1000, 2599], [2619, 2898], [2921, 2999] ];

it’s only returning 1000 and 2599 — that is ranges[0][0] and ranges[0][1]
so someone entering the postcode for Dubbo (which is in New South Wales) is ruled invalid, because its postcode — 2830 — isn’t between 1000 and 2599.

jQuery’s $.each() iterates over the first array correctly, but I’m not sure how to get the values from the second level array.

Edit:
OK, so it was a late night, and I’m blind.
kojiro has most of the answer below, and a friend here also pointed it out: I’m terminating the iteration after the first run through.
I moved that if else loop outside the iteration and just test if the postcode is within range. If is, it’s valid.
Then, if valid = true I call the confirmation function and everything else is good:

function validateAustralia(postcode, ranges) {
    for (var i = 0; i < ranges.length; i++) {
            console.log(i);
            // returns 0, 1, 2 ...
            console.log("postcode: " + postcode + " " + "ranges: " + ranges);
            // for Dubbo (2830), for example, returns postcode: 2830 ranges: 1000,2599,2619,2898,2921,2999
            console.log("ranges - low: " + ranges[i][0] + " " + "ranges - high: " + ranges[i][1]);
            // returns  ranges - low: 1000 ranges - high: 2599,
            //          ranges - low: 2619 ranges - high: 2898, ...


        if (postcode >= ranges[i][0] && (postcode <= ranges[i][1])) {
            valid = true;
        //  alert("valid =" + valid);
        } 
        if (valid === true) {
            confirmation();
            // all good
        } else {
            inelegible();
            // Sorry, mate
        }
    }
}

Because I’m new here, (long time listener, first time caller) I can’t answer my own question, but that’s basically it.

Here’s the HTML and the calling function for @nnnnnn and anyone else who wants to see:
The user chooses their state from a select

<select id="states" name="states">
     <option selected="" value="">Please choose ...</option>
        <optgroup label="Australia" id="australia">
        <option value="act">Australian Capital Territory </option>
        <option value="nsw">New South Wales </option>
      <!-- ...and so on for the rest of the states -->

and inputs their postcode into a textbox

<input id="postcode" name="postcode" type="text" maxlength="4" />

which I get thusly

postcode = $('#postcode').val();

and check against a range of postcode values

function checkAustralia(state, postcode, ranges) {  
    //      has to be in the range of values
        switch (state) {
            //Australian states
            //match the whole postcode
            //postcodes with a leading '0' are validated as whole numbers without the '0'
        case 'act':
            ranges = [ [200, 299], [2600, 2618], [2900, 2920] ];
            validateAustralia(postcode, ranges);
            break;
        case 'nsw':
            ranges = [ [1000, 2599], [2619, 2898], [2921, 2999] ];
            validateAustralia(postcode, ranges);
            break;
// ...and so on for the rest of the states

Answer 1

Your function returns false as soon as the first range is checked. Reverse that logic: return true if the value is in the range, but return false only if the loop is entirely exhausted.

Also, your code doesn’t always explicitly return a value. That isn’t obviously a problem, but it could be related to the confusion here.