Добавил реализацию String.startsWith и String.endsWith

git-svn-id: svn://192.168.3.15/activex/AVS/Sources/TeamlabOffice/trunk/OfficeWeb@64319 954022d7-b5bf-4e40-9824-e11837661b57

Common/editorscommon.js

 "use strict";
 
+if (typeof String.prototype.startsWith != 'function') {
+	String.prototype.startsWith = function (str){
+		return this.indexOf(str) === 0;
+	};
+}
+if (typeof String.prototype.endsWith !== 'function') {
+	String.prototype.endsWith = function(suffix) {
+		return this.indexOf(suffix, this.length - suffix.length) !== -1;
+	};
+}
+
 var g_sMainServiceLocalUrl = "/CanvasService.ashx";
 var g_sResourceServiceLocalUrl = "/ResourceService.ashx?path=";
 var g_sUploadServiceLocalUrl = "/UploadService.ashx";