Drop down list - display div when clicking an option

Question

You must write a function that \'shows\' the corresponding part of the form depending on what the user has selected. For example, if \'Pizza\' is selected, the div #section2

Answer 1

There are plenty of solutions for that. One of the simpliest options is to change your markup a bit and use div IDs.

HTML:

<div id="section1">
    <label for="food">What is your favourite type of food?</label>
    <select id="food" onchange="selection(this)">
        <option value="pizza">Pizza</option>
        <option value="mex">Mexican</option>
        <option value="thai">Thai</option>
    </select>
</div>
<div id="section_pizza" style="display: none;">
    What is your favourite type of pizza?<br>
    <label for="hawaiian">Hawaiian</label><input type="radio" id="hawaiian">
    <label for="supreme">Supreme</label><input type="radio" id="supreme">
    <label for="vegetarian">Vegetarian</label><input type="radio" id="vegetarian">
</div>

JavaScript:

function selection(select) {
    document.getElementById("section_" + select.value).style.display = "block";
}

---

However, you can use JQuery library and make it faster and more flexible. You can easily add animation to blocks and add extra functionality.

HTML:

<div id="section1">
    <label for="food">What is your favourite type of food?</label>
    <select id="food">
        <option value="pizza">Pizza</option>
        <option value="mex">Mexican</option>
        <option value="thai">Thai</option>
    </select>
</div>
<div id="section2" data-type="pizza" style="display: none;">
    What is your favourite type of pizza?<br>
    <label for="hawaiian">Hawaiian</label><input type="radio" id="hawaiian">
    <label for="supreme">Supreme</label><input type="radio" id="supreme">
    <label for="vegetarian">Vegetarian</label><input type="radio" id="vegetarian">
</div>

JavaScript:

$("#food").change(function() {
    $("[data-type]").hide();
    $("[data-type='" + this.value + "']").show(1000);
});

Answer 2

DEMO: http://jsfiddle.net/iambriansreed/rQr6v/

JavaScript:

var sections = {
    'pizza': 'section2',
    'mex': 'section3',
    'thai': 'section4'   
};

var selection = function(select) {

    for(i in sections)
        document.getElementById(sections[i]).style.display = "none";    

    document.getElementById(sections[select.value]).style.display = "block";

}

Checkout the demo. Replace the section3 and section4 divs with actual content.