Closure in Javascript with multiple brackets

Question

Could any one explain how this function alert, when more no of brackets of parameters are passed. I could not able to understand it clearly.

function sum(a) {

          


        

Answer 1

alert expects a string. If it doesn't get a string, it will attempt to convert whatever object it receives (and a function is a type of object) into one. If the object has a toString method, then that will be called to perform said conversion.