Javascript example

HTML

<p>
        <label for="input"><b>Nucleotide Sequence:</b><br></label>
        <textarea id="nucleotide_seq" name="nucleotide_seq" rows="6" cols="35"></textarea>
    </p>
    <input type="submit" value="Translate" onclick="translateInput()">

JavaScript

function translateInput(){
localStorage.nucle = document.getElementById("nucleotide_seq").value;
//translate nucle 
document.getElementById("nucleotide_seq").value ="converted "+localStorage.nucle;
}