Semantics!! Setting concrete definitions will necessarily make some answers and comments incompatible since they are not describing the same thing even when using the same words and phrases, but it is critical to get past the confusion (especially for new programmers).
First of all, there are multiple levels of abstraction that not everyone seems to grasp. Newer programmers who have learned on 4th or 5th generation languages may have difficulty wrapping their mind around concepts familiar to assembly or C programmers not phased by pointers to pointers to pointers. Pass-by-reference does not simply mean the ability to change a referenced object using a function parameter variable.
Variable: Combined concept of a symbol which references a value at a particular location in memory. This term is usually too loaded to be used alone in discussing details.
Symbol: Text string used to refer to variable (i.e. variable's name).
Value: Particular bits stored in memory and referenced using variable's symbol.
Memory location: Where a variable's value is stored. (The location itself is represented by a number separate from the value stored at the location.)
Function parameter: Variable declared in a function definition, used for referencing variables passed to the function.
Function argument: Variable outside the function which is passed to the function by the caller.
Object variable: Variable whose basic underlying value is not the "object" itself, rather its value is a pointer (memory location value) to another location in memory where the object's actual data is stored. In most higher-generation languages, the "pointer" aspect is effectively hidden by automatic de-referencing in various contexts.
Primitive variable: Variable whose value IS the actual value. Even this concept can be complicated by auto-boxing and object-like contexts of various languages, but the general ideas is that the variable's value IS the actual value represented by the variable's symbol rather than a pointer to another memory location.
Function arguments and parameters are not the same thing. Also, a variable's value is not the variable's object (as already pointed out by various people, but apparently ignored). These distinctions are critical to proper understanding.
Pass-by-value or Call-by-sharing (for objects): The function argument's value is COPIED to another memory location which is referenced by the function's parameter symbol (regardless of whether it's on the stack or heap). In other words, the function parameter received a copy of the passed argument's value... AND (critical) the argument's value IS NEVER UPDATED / ALTERED / CHANGED by the calling function. Remember, an object variable's value is NOT the object itself, rather it is the pointer to the object, so passing an object variable by value copies the pointer to the function parameter variable. The function parameter's value points to the exact same object in memory. The object data itself can be altered directly via the function parameter, BUT the function argument's value IS NEVER UPDATED, so it will continue to point to the same object throughout and even after the function call (even if its object's data was altered or if the function parameter is assigned a different object altogether). It is incorrect to conclude that the function argument was passed by reference just because the referenced object is updatable via the function parameter variable.
Call / Pass-by-reference: The function argument's value can/will be updated directly by the corresponding function parameter. If it helps, the function parameter becomes an effective "alias" for the argument--they effectively refer to the same value at the same memory location. If a function argument is an object variable, the ability to change the object's data is no different than the pass-by-value case since the function parameter will still point to the same object as the argument. But in the object variable case, if the function parameter is set to a completely different object, then the argument will likewise also point to the different object--this does not happen in the pass-by-value case.
JavaScript does not pass by reference. If you read closely, you will realize that all contrary opinions misunderstand what is meant by pass-by-value and they falsely conclude that the ability to update an object's data via the function parameter is synonymous to "pass-by-value".
Object clone/copy: A new object is created and the original object's data is copied. This can be a deep copy or shallow copy, but the point is that a new object is created. Creating a copy of an object is a separate concept from pass-by-value. Some languages distinguish between class object and structs (or the like), and may have different behavior for passing variables of the different types. But JavaScript does not do anything like this automatically when passing object variables. But the absence of automatic object cloning does not translate to pass-by-reference.