Dwr callback "data" object length

I'm using dwr to handle ajax calls to a java backend, I'开发者_如何学JAVAm returning a Map in java, and I need to know its size in javascript when it returns in a callback function. Is there a way to do that?

You basically need to know how to determine the size of a javascript associative array, because this is what dwr returns in this case. This is explained, of course, on Stack Overflow: Length of a JavaScript object