index.html

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<title>LiIon Production Date</title>

<div style="display:flex; justify-content:center; align-items:center; flex-direction:column;">

    <img src="https://raw.githubusercontent.com/NiklasVoigt/LiIonProductionDate/main/battery.jpg" width="40%"/>

    <div>Sony Murata Konion 18650</div>
    
    <br><br>

    <span>
    <label for="code">Datecode <span style="color: rgb(179, 179, 179);">(12 digits)</span>:</label>
    <input type="text" id="code" name="code" placeholder="e.g. 1131587AH27J">
    </span>

    <br><br>

    <button style="padding: 5px;" onclick="sony()">Get Production Date</button>

    <br><br>
    <div id="date" style="font-weight:bold;"></div>
</div>

<script>

//SONY MURATA KONION 18650 PRODUCTION DATE
function sony() {
    var yearsAlphabet = [];
    var years = [];
    var alphabet = [];
    const months = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];

    for(var i = 23; i < 26; i++) {
        yearsAlphabet.push(String.fromCharCode(65 + i));
    }

    for(var i = 0; i < 23; i++) {
        yearsAlphabet.push(String.fromCharCode(65 + i));
    }

    for(var i = 0; i < 26; i++) {
        alphabet.push(String.fromCharCode(65 + i));
        years.push(2015+i);
    }

    if (document.getElementById('code').value.length == 12) {
        var day = document.getElementById('code').value.substring(9,11) + "st";
        var month = document.getElementById('code').value.charAt(8);
        var year = document.getElementById('code').value.charAt(7);
        var history = document.getElementById('code').value.charAt(11);

        document.getElementById("date").style.color = "green";
        document.getElementById("date").innerHTML = day + " " + months[alphabet.indexOf(month)]  + " " + years[yearsAlphabet.indexOf(year)] + " with electrode history code " + history;
    } else {
        document.getElementById("date").style.color = "red";
        document.getElementById("date").innerHTML = "Datecode not valid";
    }
    
}


</script>