是否可以在js脚本中包含一个php文件并访问该php文件的功能？

I have js file where i need to call the function defined in the php file to calculate the value and then move on to next step. Is this possible to do? I am not able to access the function of the php file from my script. Also is there some way around to include php file in a html page without changing the extention I have js file where i need to call the functio