Exceptions

var problem = false;

function C() {
    if (problem) throw "Doh!";
    console.log("exiting C normally");
}

function B() {
    C();
    console.log("exiting B normally");
}

function A() {
    B();
    console.log("exiting A normally");
}

function A2() {
    try { B() }
    catch(err) { console.log("had error '"+err+"', but now...")} //clears error
    console.log("exiting A2 normally");
}

function A3() {
    try { B() }
    finally { console.log("exiting A3") }//runs always, but any error remains
    console.log("normally");
}

function A4() {
    try { B() }
    catch(err) { console.log("had error '"+err+"', but now...")} //clears error
    finally {console.log("exiting A4") }//runs always
    console.log("normally");
}


try {
    A();
}
catch(err) { //won't run unless problem
    console.log(err);
}