<input type="text" class="form-control" name="myvalue1" id="myvalue1" value="Merhaba Dünya 1!" readonly />
<button onclick="copyToClipboard('myvalue1')">Copy myvalue</button>


<input type="text" class="form-control" name="myvalue2" id="myvalue2" value="Merhaba Dünya 2!" readonly />
<button onclick="copyToClipboard('myvalue2')">Copy myvalue</button>

<script>
    function copyToClipboard(elm) {
        var textBox = document.getElementById(elm);
        textBox.select();
        document.execCommand("copy");
    }
</script>