comparing values of array and fill dropdown

Question

I have two array

  array1[1;2;3;] 
  array2[1;1;1;1;2;2;3;3;]

I filled 1st array in dropdown menu. Now i need to check if in 2nd array is elements with same value "1;" and on select fill dropdown2 with elements of array2 with same value. I just need example of code.

You can use this selfwritten Array-method: [Comparing two arrays in Javascript](http://stackoverflow.com/questions/7837456/comparing-two-arrays-in-javascript) — alexP, Aug 20 '13 at 09:18
Edit ur question post and give additional details like your requirement,what you have done so far,In which stream you need help,what is your desired output.This post doesn't explain anything and makes no sense. — Sasidharan, Aug 20 '13 at 09:20
well when i explained to detailes no1 answered so i tryed to explain now as simple as i could... here is http://stackoverflow.com/questions/18328681/checking-values-of-arrays with much more details — user2599279, Aug 20 '13 at 09:22

score 1 · Accepted Answer · answered Aug 20 '13 at 10:13

I created a jsFiddle which may help you achieve your goal: http://jsfiddle.net/XTdrr/

The initial HTML:

<select id="select1" onChange="populateSelect2()">
    <option value="">Choose...</option>
</select>
<br/>
<select id="select2"></select>

The initial JavaScript variables

var array1 = [1, 2, 3];
var array2 = [1, 1, 1, 1, 2, 2, 3, 3];

var select1 = document.getElementById("select1");
var select2 = document.getElementById("select2");

First, it populates the first dropdown list with the values in array1.

window.onload = function () {

    // here we populate select1 with the elements in array1

    for (var i = 0; i < array1.length; i++) 
    {
        var opt = document.createElement('option');
        opt.value = array1[i];
        opt.innerHTML = array1[i];
        select1.appendChild(opt);
    }
}

When something is selected int the first dropdown, it looks for matching elements in array2 and populates the second dropdown with those.

function populateSelect2() 
{
    // first, empty select2

    for (var i = select2.options.length - 1; i >= 0; i--) 
    {
        select2.remove(i);
    }

    // then add new items
    // based on the selected value from select1 and matches from array2

    for (var i = 0; i < array2.length; i++) 
    {
        if (array2[i] == select1.value) 
        {
            var opt = document.createElement('option');
            opt.value = array2[i];
            opt.innerHTML = array2[i];
            select2.appendChild(opt);
        }
    }
}

comparing values of array and fill dropdown

1 Answers1