JavaScript: get value of dropdown

Question

I have 3 HTML combo/drop down boxes. All of them have a distinct name and id. On a particular event I want to get the value of all three of them. Can any one give me a code snippet for that?

Answer 1

using jQuery:

$("#dropdownID").val();

Answer 2

Use a framework like jQuery mentioned above or just do it the old school way. document.getElementById('dropdownId').value .

Answer 3

To do this not using jQuery:

function getSelectValues() {
    var values = [];
    for (var i = 0; i < arguments.length; i++) {
        var select = document.getElementById(arguments[i]);
        if (select) {
            values[i] = select.options[select.selectedIndex].value;
        } else {
            values[i] = null;
        }
    }
    return values;
}

This function returns an array of values that correspond to the ids you pass into the funtion, as follows:

var selectValues = getSelectValues('id1', 'id2', 'id3');

If a <select> with one of your specified ids does not exist the array contains null for the value for that position.

There are a couple of other ways to do this, you could pass the function an array of id values: getSelectValues([ 'id1', 'id2', 'id3' ]), in which case the function would be changed:

function getSelectValues(ids) {
    var values = [];
    for (var i = 0; i < ids.length; i++) {
    // ...

You could also pass the function a map of ids and populate the values:

var myMap = { 'id1': null, 'id2': null, 'id3': null };
getSelectValues(myMap);
// myMap['id1'] contains the value for id1, etc

This would change the function to be:

function getSelectValues(map) {
    for (var id in map) {
        var select = document.getElementById(id);
        if (select) {
            map[id] = select.options[select.selectedIndex].value;
        } else {
            map[id] = null;
        }
    }
}

Answer 4

I'd try to set them up next to each other in your HTML and then iterate through them using jQuery's built-in each() method. You'd set up your elements like this:

<div id="dropdownBoxes">
<select id="firstElement">
    <option>cool</option>
    <option>neat</option>
</select>
<select id="secondElement">
    <option>fun</option>
    <option>awesome</option>
</select>
<select id="thirdElement">
    <option>great</option>
    <option>synonym</option>
</select>
</div>

<input type="button" id="theTrigger">Push me!</input>

Then, in your script:

var dropdownValues;

$("#theTrigger").click(function(){    
dropdownValues.length=0;
$("#dropdownBoxes select").each(function(){
    dropdownValues.push($(this).val());
    });
});