A stupid Ajax cache problem solution

One of the common problem using Ajax (Flash too) interactions is the cache.
There are a lot of valid PHP, Python, JSP and .NET solutions but browser compatibility is often a question mark.

You could implement easyly and directly a client solution and this is just another proposal.

function noCache(uri){return uri.concat(/\?/.test(uri)?"&":"?","noCache=",(new Date).getTime(),".",Math.random()*1234567)};

exactly 123 bytes to solve cache problems and this is the func description:

function noCache(
  uri  
  // uri string to open
 ){

 return uri.concat( 
  // concat String prototype,
  // the fastest way to produce
  // a complete string using multiple values

  /\?/.test(uri) ?
  // if uri has a query string

   "&"
  // add last value using & separator char
   :

  // else
   "?",
  // add a query string to this url

  "noCache=",
  // this should be a "cool name" for generated key

  (new Date).getTime(),
  // the noCache value will be milliseconds
  // from 1970/01/01

  ".",
  // plus a dot ...

  Math.random()*1234567
  // ... and a random value using
  // a "big" integer as generator
 );

 // then this is a return example using uri: http://host.com/mypage.html
 // http://host.com/mypage.html?noCache=1166301156233.332083.6663326991

 // while this is an example using uri: http://host.com/mypage.html?v0=1&v2=a
 // http://host.com/mypage.html?v0=1&v2=a&noCache=1166301168420.631416.7190624559
};

You could test directly in a loop, a benchmark that many other sites didn't test ...

for(var
 i = 0,    // many loops
 max = 10000,   // max i value
 uri = document.location.href, // this href
 obj = {};   // a generic object
 i < max;   // while i is less than max
 i++    // increment the i value
) {
 if(!obj[noCache(uri)])  // if obj has not a nocache(uri) key
  obj[noCache(uri)] = true; // set them as true
 else {    // else if obj has just the returned nocache(uri) key
  i = max;
  alert("noCache doesn't work"); // this method is not so cool
 }
};

A script that use Ajax requestes inside a loop is not a good script (I suppose) but this kind of demostration can show You that generated no-cache collisions probability are quite impossible.

A usage example should be this one:

XHR.open("get", noCache(myUri), true);
// or ...
XHR.open("post", noCache(myUri2), true);

Finally these are some F.A.Q.

Why there is a key and a value and not just a random value to perfom without caching problems ?
- because some server-side code should loop over GET or POST keys and in this way it should know that noCache is a not useful parameter to parse or to check. In other cases a server-side code should consider generated radom value as a key.

Why there is a getTime plus a random value and not just the first one ?
- because some client application should call more than a single request at the same time

Why there is a full stop between getDate and random value ?
- because if client date is modified there are less possibilities that generated value was just used (paranoia style)

I think these F.A.Q. are enought and I hope You'll find this simple function useful :-)

P.S. with ActionScript just change the regExp replacing with uri.indexOf("?") >= 0