Javascript: Only using specific parameter in function

function-parameter, javascript

Solution

You can check each parameter separately using an `if(param)`, like:

function test(para_1, para_2, para_3) {
    if (para_1) {
        // First parameter set
    }
    if (para_2) {
        // Second parameter set
    }
    if (para_3) {
        // Third parameter set
    }
}

Generally speaking, you cannot set only one parameter and expect it to be the third, because it will automatically set it to the first one, and the remaining 2 as `undefined`. So if you would like to call your function and only have the third set, most probably you'd do a

test(null, null, 'this_is_set');

Problem

I think it is rather a beginner's question: How can I address a specific parameter in a function and ignore the others? Example: http://jsfiddle.net/8QuWj/ ``` function test(para_1, para_2, para_3) { if (para_3 == true) { alert('only the third parameter was successfully set!'); } } test(para_3=true); ``` I want to individually decide whether or not I use a certain parameter in a function or not.

Original source