PHP's in_array was created before jQuery's inArray, so I'm not sure of the origin of the choice of function name jQuery took, but if it was from PHP, they either named the function incorrectly or created the function with a return value that is incorrect. I am leaning toward naming it incorrectly.
An English sentence would say, "If an element is in an array, do something, otherwise do something else." That sentence is based on a boolean condition and in no way is asking to "do something" based on the position of the element in the array. Therefore, a function name of inArray should return a boolean value, not a numeric position. I vote to change the name of the function to something more intuitive, like posInArray, indexOf, indexInArray... so on and so on. Anyone else agree?
