Drag and drop problem

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C#

ASP.NET

Javascript

HTML

HELLO
IAM IMPLEMENTING DRAG AND DROP FEATURES IN MY WEBSITE which is actually an online drag drop website builder.ACTUALLY THERE IS A TOOLBAR ON THE TOP OF THE PAGE .WHENEVER USERS DRAGS SOME CONTROL FROM THE TOOLBAR AND DROPS IT IN THE SPECIFIED AREA .SO a new instance of that particular control shud be generated .Actually the problem iam having is that all the help i got on internet regarding drag and drop is to drag that particular item but i want to create a new instance so what should i do.
my second query is that i want to show the page with the toolbar and the users page in the same page . im currently using iframes for that but the problem is i want to edit the html of the user's webpage .so what should i use
please do help me as im in a bit of bother
THanking in anticipation :) cheers