Whenever there is dilemma to do a particular task, which can be accomplished either by client side code or by using a server code, which should be preferred?
For example:
I can iterate through a javascript object and construct a string and then send it to server, or should i send the javascript object and process it in the server?
My views: whenever I come across this situation I use the client side code as it reduces the computation load on server. 
What has to be done in such a situation? Which is the right approach?
String manipulation is pretty fast in the server side but it's fine to do on the client side too. However make sure to validate the string once it arrives at the server side because any client can replicate requests to your server with a string and try to cause trouble.
Design issue: client side or server side?