After I die I want to have a touch Restart-button on Android.
I tried it in javascript, but it doesn’t work:
function OnMouseDown ()
{
Application.LoadLevel(Application.loadedLevel);
}
I read, that there should be a function update, but I don’t now how 
Hello, this is my first answer in this forum but AFAIK, OnMouseDown needs a box collider/circle collider(if your button is round). And you need to enter level name inside LoadLevel parenthesis
eg:
Application.LoadLevel(“level1”);
@codekidX, Application.LoadLevel has two overloads, one takes the level name by string the other takes the index of the level based off the order in build settings. [Application.loadedLevel][1] returns the index or type of int [Application.loadedLevelName][2] returns the name of the level or type of string Either can be passed to LoadLevel and the appropriate overload for the method LoadLevel will be selected by parameter type. [1]: http://docs.unity3d.com/ScriptReference/Application-loadedLevel.html [2]: http://docs.unity3d.com/ScriptReference/Application-loadedLevelName.html
– Landern
But what is your restart button? I would guess you have this on a GameObject, GUIElement or a GameObject with a collider.
– fafase