You need to convince your manager of something. That's an art form you learn to perfect :-)
Show them equivalent bits of code for doing a simple function in ASP, straight JS and jQuery, and choose a sample that ensures the straight JS version is large and hideous.
Tell them you fully agree with their concerns on ASP (butter them up, that always works well) but that you have concerns on quality and timeliness of delivery (this will scare the living daylights out of any manager).
Your carefully selected samples should convince them that they should move from ASP to jQuery rather than ASP to straight JS. Or, worst case, they'll stay with ASP for a bit longer.
Both these sound acceptable to you since they don't involve heavy lifting.
I like to take my cues from the "Yes, Prime Minister" show where Sir Humphrey once commented (paraphrased):
Give them three options, two of which can be shown to eventually culminate in World War III, then let them think about it for a bit.