<%@ LANGUAGE="JavaScript" %> <% /*** Clock -- beginning of server-side support code by Andrew Shearer, http://www.shearersoftware.com/ v2.1-ASP, 2002-10-12. For updates and explanations, see <http://www.shearersoftware.com/software/web-tools/clock/>. ***/ /* Prevent this page from being cached (though some browsers still cache the page anyway, which is why we use cookies). This is only important if the cookie is deleted while the page is still cached (and for ancient browsers that don't know about Cache-Control). If that's not an issue, you may be able to get away with "Cache-Control: private" instead. */ Response.AddHeader("Pragma", "no-cache"); /* Grab the current server time. */ var gDate = new Date(); /* Are the seconds shown by default? When changing this, also change the JavaScript client code's definition of clockShowsSeconds below to match. */ var clockShowsSeconds = false; function getServerDateItems() { return gDate.getFullYear()+","+gDate.getMonth()+","+gDate.getDate()+"," +gDate.getHours()+","+gDate.getMinutes()+","+gDate.getSeconds(); } function clockDateString(inDate) { return ["Sunday, ","Monday, ","Tuesday, ","Wednesday, ", "Thursday, ","Friday, ","Saturday, "][inDate.getDay()] + ["January ","February ","March ","April ","May ","June ", "July ", "August ","September ","October ","November ","December "] [inDate.getMonth()] + inDate.getDate() + ", " + inDate.getFullYear(); } function clockTimeString(inHours, inMinutes, inSeconds) { return (inHours == 0 ? "12" : (inHours <= 12 ? inHours : inHours - 12)) + (inMinutes < 10 ? ":0" : ":") + inMinutes + (clockShowsSeconds ? ((inSeconds < 10 ? ":0" : ":") + inSeconds) : "") + (inHours < 12 ? " AM" : " PM"); } /*** Clock -- end of server-side support code ***/ %> <html> <head> <title>Clock</title> <meta name="template" content="none"> <script language="JavaScript" type="text/javascript"> <!-- /* set up variables used to init clock in BODY's onLoad handler; should be done as early as possible */ var clockLocalStartTime = new Date(); var clockServerStartTime = new Date(<%=getServerDateItems()%>); /* stub functions for older browsers; will be overridden by next JavaScript1.2 block */ function clockInit() { } //--> </script> <script language="JavaScript1.2" type="text/javascript"> <!-- /*** simpleFindObj, by Andrew Shearer Efficiently finds an object by name/id, using whichever of the IE, classic Netscape, or Netscape 6/W3C DOM methods is available. The optional inLayer argument helps Netscape 4 find objects in the named layer or floating DIV. */ function simpleFindObj(name, inLayer) { return document[name] || (document.all && document.all[name]) || (document.getElementById && document.getElementById(name)) || (document.layers && inLayer && document.layers[inLayer].document[name]); } /*** Beginning of Clock 2.0, by Andrew Shearer See: http://www.shearersoftware.com/software/web-tools/clock/ Redistribution is permitted with the above notice intact. Client-side clock, based on computed time differential between browser & server. The server time is inserted by server-side JavaScript, and local time is subtracted from it by client-side JavaScript while the page is loading. Cookies: The local and remote times are saved in cookies named localClock and remoteClock, so that when the page is loaded from local cache (e.g. by the Back button) the clock will know that the embedded server time is stale compared to the local time, since it already matches its cookie. It can then base the calculations on both cookies, without reloading the page from the server. (IE 4 & 5 for Windows didn't respect Response.Expires = 0, so if cookies weren't used, the clock would be wrong after going to another page then clicking Back. Netscape & Mac IE were OK.) Every so often (by default, one hour) the clock will reload the page, to make sure the clock is in sync (as well as to update the rest of the page content). Compatibility: IE 4.x and 5.0, Netscape 4.x and 6.0, Mozilla 1.0. Mac & Windows. History: 1.0 5/9/2000 GIF-image digits 2.0 6/29/2000 Uses text DIV layers (so 4.0 browsers req'd), & cookies to work around Win IE stale-time bug 2.1 10/12/2002 Noted Mozilla 1.0 compatibility; released PHP version. */ var clockIncrementMillis = 60000; var localTime; var clockOffset; var clockExpirationLocal; var clockShowsSeconds = false; var clockTimerID = null; function clockInit(localDateObject, serverDateObject) { var origRemoteClock = parseInt(clockGetCookieData("remoteClock")); var origLocalClock = parseInt(clockGetCookieData("localClock")); var newRemoteClock = serverDateObject.getTime(); // May be stale (WinIE); will check against cookie later // Can't use the millisec. ctor here because of client inconsistencies. var newLocalClock = localDateObject.getTime(); var maxClockAge = 60 * 60 * 1000; // get new time from server every 1hr if (newRemoteClock != origRemoteClock) { // new clocks are up-to-date (newer than any cookies) document.cookie = "remoteClock=" + newRemoteClock; document.cookie = "localClock=" + newLocalClock; clockOffset = newRemoteClock - newLocalClock; clockExpirationLocal = newLocalClock + maxClockAge; localTime = newLocalClock; // to keep clockUpdate() happy } else if (origLocalClock != origLocalClock) { // error; localClock cookie is invalid (parsed as NaN) clockOffset = null; clockExpirationLocal = null; } else { // fall back to clocks in cookies clockOffset = origRemoteClock - origLocalClock; clockExpirationLocal = origLocalClock + maxClockAge; localTime = origLocalClock; // so clockUpdate() will reload if newLocalClock // is earlier (clock was reset) } /* Reload page at server midnight to display the new date, by expiring the clock then */ var nextDayLocal = (new Date(serverDateObject.getFullYear(), serverDateObject.getMonth(), serverDateObject.getDate() + 1)).getTime() - clockOffset; if (nextDayLocal < clockExpirationLocal) { clockExpirationLocal = nextDayLocal; } } function clockOnLoad() { clockUpdate(); } function clockOnUnload() { clockClearTimeout(); } function clockClearTimeout() { if (clockTimerID) { clearTimeout(clockTimerID); clockTimerID = null; } } function clockToggleSeconds() { clockClearTimeout(); if (clockShowsSeconds) { clockShowsSeconds = false; clockIncrementMillis = 60000; } else { clockShowsSeconds = true; clockIncrementMillis = 1000; } clockUpdate(); } function clockTimeString(inHours, inMinutes, inSeconds) { return inHours == null ? "-:--" : ((inHours == 0 ? "12" : (inHours <= 12 ? inHours : inHours - 12)) + (inMinutes < 10 ? ":0" : ":") + inMinutes + (clockShowsSeconds ? ((inSeconds < 10 ? ":0" : ":") + inSeconds) : "") + (inHours < 12 ? " AM" : " PM")); } function clockDisplayTime(inHours, inMinutes, inSeconds) { clockWriteToDiv("ClockTime", clockTimeString(inHours, inMinutes, inSeconds)); } function clockWriteToDiv(divName, newValue) // APS 6/29/00 { var divObject = simpleFindObj(divName); newValue = '<p>' + newValue + '<' + '/p>'; if (divObject && divObject.innerHTML) { divObject.innerHTML = newValue; } else if (divObject && divObject.document) { divObject.document.writeln(newValue); divObject.document.close(); } // else divObject wasn't found; it's only a clock, so don't bother complaining } function clockGetCookieData(label) { /* find the value of the specified cookie in the document's semicolon-delimited collection. For IE Win98 compatibility, search from the end of the string (to find most specific host/path) and don't require "=" between cookie name & empty cookie values. Returns null if cookie not found. One remaining problem: Under IE 5 [Win98], setting a cookie with no equals sign creates a cookie with no name, just data, which is indistinguishable from a cookie with that name but no data but can't be overwritten by any cookie with an equals sign. */ var c = document.cookie; if (c) { var labelLen = label.length, cEnd = c.length; while (cEnd > 0) { var cStart = c.lastIndexOf(';',cEnd-1) + 1; /* bug fix to Danny Goodman's code: calculate cEnd, to prevent walking the string char-by-char & finding cookie labels that contained the desired label as suffixes */ // skip leading spaces while (cStart < cEnd && c.charAt(cStart)==" ") cStart++; if (cStart + labelLen <= cEnd && c.substr(cStart,labelLen) == label) { if (cStart + labelLen == cEnd) { return ""; // empty cookie value, no "=" } else if (c.charAt(cStart+labelLen) == "=") { // has "=" after label return unescape(c.substring(cStart + labelLen + 1,cEnd)); } } cEnd = cStart - 1; // skip semicolon } } return null; } /* Called regularly to update the clock display as well as onLoad (user may have clicked the Back button to arrive here, so the clock would need an immediate update) */ function clockUpdate() { var lastLocalTime = localTime; localTime = (new Date()).getTime(); /* Sanity-check the diff. in local time between successive calls; reload if user has reset system clock */ if (clockOffset == null) { clockDisplayTime(null, null, null); } else if (localTime < lastLocalTime || clockExpirationLocal < localTime) { /* Clock expired, or time appeared to go backward (user reset the clock). Reset cookies to prevent infinite reload loop if server doesn't give a new time. */ document.cookie = 'remoteClock=-'; document.cookie = 'localClock=-'; location.reload(); // will refresh time values in cookies } else { // Compute what time would be on server var serverTime = new Date(localTime + clockOffset); clockDisplayTime(serverTime.getHours(), serverTime.getMinutes(), serverTime.getSeconds()); // Reschedule this func to run on next even clockIncrementMillis boundary clockTimerID = setTimeout("clockUpdate()", clockIncrementMillis - (serverTime.getTime() % clockIncrementMillis)); } } /*** End of Clock ***/ //--> </script> </head> <body bgcolor="#FFFFFF" onload="clockInit(clockLocalStartTime, clockServerStartTime);clockOnLoad();" onunload="clockOnUnload()"> <div id="ClockTime" style="position: absolute; left: 406px; top: 28px; width: 200px; height: 20px; z-index: 11; cursor: pointer" onclick="clockToggleSeconds()"> <p><%=clockTimeString(gDate.getHours(), gDate.getMinutes(), gDate.getSeconds())%></p> </div> <div id="ClockBkgnd" style="position: absolute; left: 406px; top: 28px; width: 200px; z-index: 10"> <p> <br> <%=clockDateString(gDate)%></p> </div> <p><i>Click on the time to show or hide seconds.</i></p> </body> </html>