How to response the different js content by src parameter in backend

When I use a jssdk, i found the response are different when i pass param or no param.

<script src='https://captcha.guard.qcloud.com/template/TCapIframeApi.js?appid=1252580571&clientype=1&lang=2052&asig=zS8Ivp_XDl-h2W5-VTC5IgyYMrk4e-kcnG03Ti_d5xZHNxvNCzCX5S5PN7AdQRK_JvTIP-HTao3uHMTmEaJeoB7SYqcE7WOl'></script>

<script src='https://captcha.guard.qcloud.com/template/TCapIframeApi.js'></script>

Is't changed in backend and how this is done?