Text Display

Hi

I am trying to display text on mouse click but somehow it doesn’t show in gui.textarea.
thanks in advance for any help and suggestions on better ways.
here is my code:

public class ReadText : MonoBehaviour {

public TextAsset TestText1;
public TextAsset TestText2;
//public GameObject GB1;
//public GameObject GB2;
private string TextContent;
private string CtnShow;
// Use this for initialization
void Start () {
	TextContent = " ";
}

// Update is called once per frame
void OnGUI () {
	GUI.TextArea (new Rect (10, 10, 400, 200), TextContent, 480);
}
void OnMouseDown(){
	if (tag == "En") {
		TextContent = TestText1.text;
	}
	if (tag == "Fa") {
		TextContent = TestText2.text;
	}
}

Looks like tag is not getting set, try a Debug.Log("Tag = " + tag); just before your if statements (line 20) so you can see what it is, then you can start looking around to see why it’s not what you think it should be.