Optional Parameters and Default Arguments

function testFunction(a,b,c) {
   // this says 'if the type of a is undefined, set it to '', otherwise set it 
   // to a (e.g. itself)'
   a = (typeof(a) == undefined) ? '' : a;   
   b = (typeof(b) == undefined) ? '' : b;     
   c = (typeof(b) == undefined) ? '' : c;
}