c＃通过AJAX调用数据到网页错误

I am trying to do this for the first time based on modifying a code snippet I found online. I am building an html data table in my code behind embedding sql data from a c# datatable. I am then trying to pass it to an .aspx page using an AJAX call and passing the html table string to a tag. The problem I am having is that when I breakpoint on the htmlTable string it looks good but the page is coming up with a javascript alert box saying 'error', not sure how to troubleshoot from this point or what is wrong with the code, I have pasted below, any assistance is appreciated!!! Code Behind:I am trying to do this for the first time based