situation is like this. A page has  evaluation module, details module, and image module . The backend sets up three corresponding APIs respectively, because the whole page builds the dom template from the details module, that is, the image and the evaluation backend will each return a data, which needs me to fill in the details module. Is there any way for me  to call the ajax method of the evaluation and then the ajax  of the image?  finally  then summarize the two important data into the details of the core module? Is there any way to let the first two functions execute first and get the results I want before continuing with the last function? 
 here"s what I wrote: 
 does this method guarantee that getPic,getEva is executed first? 
function getDetali(){  //
getPic()//
getEva()//
if(xxxxx){
   showDetail() //
}
}