Build Pagination Link Using Auto Incremented Sequential Number

I am using this script called virtualpaginate, I have it all working but there is one thing that I would like to change. currently it displays all the paginated page number, I have 14 so it looks like "1 2 3 4 5 ... 14", What I would like to do is change the script so it will show " 1 2 3 4" once you click 4, 5 will appear once you click 5, 6 will appear and so on. I am completely stuck on how I can archive this. The section of the code I need to change is below:

Code:
virtualpaginate.prototype.paginate_output_flatview=function(flatviewcontainer, divpos, anchortext){
var flatviewhtml=""
var anchortext=anchortext || new Array()
for (var i=0; i<this.pagecount; i++){
if (typeof anchortext[i]!="undefined") //if custom anchor text for this link exists
flatviewhtml+='<a href="#flatview" rel="'+i+'">'+anchortext[i]+' |</a> ' //build pagination link using custom anchor text
else
flatviewhtml+='<a href="#flatview" rel="'+i+'">'+(i+1)+'</a> | ' //build pagination link using auto incremented sequential number instead
}
flatviewcontainer.innerHTML=flatviewhtml
this.paginate_build_flatview(flatviewcontainer, divpos, anchortext)
}