Easy javascript question - calling a property of type function by name?

What about

var obj={};
obj.test1=function(a){console.log("test1­ called"+a);};

function jstest(funname,argument) {
  if (obj[funname] !== undefined) { //or if (typeof obj[funname] === 'function') ??
    obj[funname](argument);
  }
}

jstest("test1", "test");

Not tested.