By differ if you meant accessing them and their values using different handles, you can do that just by accessing their ids.
use $("#mlti_1")
for accessing the chosen
control and $("#mult_2")
for the second multiselect control.
UPDATE :
As I said in the comment, you can use the following function to determine the type of the multi-select.
function displayType(id) // id = mult_val or drp_me
{
var control = document.getElementById(id);
console.log(control.type); // both controls showing as select-multiple
if (control.classList.contains("chosen")) {
console.log("chosen");
} else if (control.classList.contains("select2")) {
console.log("select2");
}
}
provided, you assign proper class names(chosen and select2) to the various multi-selects in the HTML code.