There are many reasons a web developer might have to think of the Javascript Open Excel function. In any case we'll try and make it as easy as possible to opening excel using js.
Here's the Javascript Open Excel Code:
var newwindow=window.open("url to.xls","window2","");
another option would be to use this Javascript OpenExcel Function in the header of your page:
Javascript Open Excel is not really that complicated. Keep in mind that viewers will not be able to save or write to your webserver unless it is local.