Need if-else advice in actionscript3

Question

function clickButtonHandler(event:MouseEvent):void
{
    var message:Object = new Object();
    message.text = txtMessage.text;
    message.userName = txtUser.text;
    //Posts to this swf
    showMessage(message);
    //Posts to ALL OTHER swf files..
    group.post(message);

}

function showMessage(message:Object):void
{
    output_txt.appendText(message.userName+": "+message.text + "\n");

}

function jsalertwindow(event:MouseEvent):void
{
    var alert:URLRequest = new URLRequest("javascript:alert('Please enter your User name')");
    navigateToURL(alert, "_self");
}

As you can see there are two function which are contain mouseevent. I want to send those function with an if-else statement. If user write something in text input component which name is txtUser and,

send_btn.addEventListener(MouseEvent.CLICK, clickButtonHandler);

will work, else(if the user forget writing anything)

send_btn.addEventListener(MouseEvent.CLICK, jsalertwindow);

will work. And one more question should i use MouseEvent.CLICK or MouseEvent.MOUSE_DOWN? Thanks for your advice.

Answer 1

Assign a single handler to the button click (MouseEvent.CLICK is the right event to use) and check the field is populated in the handler:

function clickButtonHandler(event:MouseEvent):void
{
    var message:Object = new Object();

    // Check the field is populated
    if (txtUser.text != "")
    {
        message.text = txtMessage.text;
        message.userName = txtUser.text;

        showMessage(message);
        //Posts to ALL OTHER swf files..
        group.post(message);
    } 
    else 
    {
        // Nothing in the input field, show the alert
        showAlert();
    }
}

function showMessage(message:Object):void
{
    output_txt.appendText(message.userName+": "+message.text + "\n");

}

function showAlert():void
{
    var alert:URLRequest = new URLRequest("javascript:alert('Please enter your User name')");
    navigateToURL(alert, "_self");
}