<input autocomplete="off" class="form-control amount input-lg" id="inputAmountCrypto" onchange="updateCurrencyLTC(value)" name="crypt_amount" placeholder="0.00144467" type="text" value="">
<?php
echo "<script>";
echo "function updateCurrencyLTC(value) {";
echo "document.getElementById(\"inputAmountUsd\").innerHTML = value * $ltc;";
echo "}";
echo "</script>"
?>