php如何获取到这个网站下拉加载出来的ajax内容？

Question

目标网站是：http://www.vlook.cn/app/square/category?r=re&catId=1156&no=4

ajax的URL是：http://www.vlook.cn/ajx/n/square/category?cid=1156&scrollSpan=25&no=76&size=12&sid=3&rnd=0.5945953091140836

每下拉加载的URL：
http://www.vlook.cn/ajx/n/square/category?cid=1156&scrollSpan=25&no=77&size=12&sid=3&rnd=0.4636393147520721
http://www.vlook.cn/ajx/n/square/category?cid=1156&scrollSpan=25&no=78&size=12&sid=3&rnd=0.5662677509244531
http://www.vlook.cn/ajx/n/square/category?cid=1156&scrollSpan=25&no=80&size=12&sid=3&rnd=0.9569658676628023

不知道怎么获取到这个ajax的URL，URL的rnd=0.5945953091140836参数是会变的，
查看JS文件：http://image.vlook.cn/js/v3/v106_vlk.square_category-min.js?ver=1.2.6
也没有发现rnd参数，请教大家了！