Web Storage test

HTML

<p>
    <input type="text" id="session">
    <button type="button" onclick="store('session');">set sessionStorage</button>
</p>
<p>
    <input type="text" id="local">
    <button type="button" onclick="store('local');">set localStorage</button>
        
</p>

<p>
    <button type="button" onclick="clearstore();">clear session</button>
    </p>

JavaScript

var store; //defined as function later
(function() {

    function byId(id) {
        return document.getElementById(id);
    }
    var key = 'mytest';

    store = function(type) {
        //type corresponds both to storage type and id of textbox.
        var
        value = byId(type).value,
            storage = window[type + 'Storage'];

        if (value) {
            storage.setItem(key, value);
        } else {
            storage.removeItem(key);
        }
    }

    window.onload = function() {
        //pre-fill fields based on currently-stored values
        byId('session').value = sessionStorage.getItem(key);
        byId('local').value = localStorage.getItem(key);
    };

}());

function clearstore(){
	sessionStorage.clear();
}