adding onchange ONLY if function zzz exist

[Mel]

I would like to add onChange to a select only if a javascript function
zzz exist.

can this be done ?

example is highly appreciated

 

[scripts.contact]

I would like to add onChange to a select only if a javascript function
zzz exist.

can this be done ?

example is highly appreciated

if(window.zzz && /function/i.test(typeof(zzz))){
// add onchange event to select element

}