EditorApplication.timeSinceStartup 自开始的时间

// Simple editor window that autosaves  the working scene  
//简单的编辑器窗口,可以自动保存工作场景
// Make sure to have this window opened to be able to execute the auto save. 
//确保这个窗口开着, 这样才能执行自动保存

import UnityEditor;

class SimpleAutoSave extends EditorWindow {

	var saveTime : float = 300;
	var nextSave : float = 0;

	@MenuItem("Example/Simple autoSave")
	static function Init() {
		var window : SimpleAutoSave =
		EditorWindow.GetWindowWithRect(
		SimpleAutoSave,
		Rect(0,0,165,40));
		window.Show();
	}
	function OnGUI() {
		EditorGUILayout.LabelField("Save Each:", saveTime + " Secs");
		var timeToSave : int = nextSave - EditorApplication.timeSinceStartup;
		EditorGUILayout.LabelField("Next Save:", timeToSave.ToString() + " Sec");
		this.Repaint();

		if(EditorApplication.timeSinceStartup > nextSave) {
			var path : String [] = EditorApplication.currentScene.Split(char.Parse("/"));
			path[path.Length -1] = "AutoSave_" + path[path.Length-1];
			EditorApplication.SaveScene(String.Join("/",path));
			Debug.Log("Saved Scene");
			nextSave = EditorApplication.timeSinceStartup + saveTime;
		}
	}
}