js加密参数encodeURIComponent，php解密参数urldecode

window.location.href='download_file?text=' + encodeURIComponent(text) + '&voice=' + voice + '&speech_rate=' + speech_rate;

if (!$text = trim($_REQUEST['text'])) {
    $this->json->E('请输入文本内容');
}
$text = urldecode($text);

避免特殊字符，影响参数传递。