How can I select my target character style from the dropdown list of the panel?

//call the makeDialog function
makeDialog();
//cs will hold the result
var cs;   
function makeDialog(){
    //the dialog object
    var theDialog = app.dialogs.add({name:"Choose a Style", canCancel:true});
    //add a dropdown list object, stringList gets the name of every available character style
    //note this would not get grouped styles
    with(theDialog.dialogColumns.add()){
        cs = dropdowns.add({stringList:app.activeDocument.characterStyles.everyItem().name, selectedIndex:0, minWidth:80});
    }
    if(theDialog.show() == true){
        //get the result
        cs = app.activeDocument.characterStyles.item(cs.selectedIndex);
        //call the main() function
        main();
        theDialog.destroy();
	}
}


function main(){
    alert("Chosen Style’s name: " + cs.name);
    //Do something with the preset here
}