Javascript: url containing random number

Question

A friend is linking my page from his site. As I need users to avoid caching when visiting my page, I want the url to have this form:

http://www.mypage.com/index.php?456646556

Where 456646556 is random number.

As my friend does not have installed php, how can I build the link with the random number using Javascript?

Also my friend asked me to give him just the url, with no further functions as his page is already loaded with them. Can it be done?

Thanks a lot

Solution 1

I would add a parameter but you can leave it out if needed:

var url = "http://www.mypage.com/index.php?rnd="+Math.random()

or

var url = "http://www.mypage.com/index.php?rnd="+new Date().getTime()

Link:

<a href="http://www.mypage.com/index.php?rnd=1" onClick="this.href=this.href.split('?')[0]+'?rnd='+new Date().getTime()">Mostly random</a>

Note that if you have more than one assignment - for example in a loop, you need to add to the getTime since an iteration of the loop is faster than a millisecond:

var rnd = new Date().getTime();
for (var i=0;i<links.length;i++) {
   links[i].href = "http://www.mypage.com/index.php?rnd="+(rnd+i);
}

UPDATE to use the URL constructor with searchParams

const addRnd = urls => {
  let rnd = new Date().getTime();
  return urls.map((urlStr,i) => {
    let url = new URL(urlStr);
    url.searchParams.set("rnd",rnd+i);  // in case called multiple times
    return url;
  });
};
const urls = addRnd( ["http://www.mypage.com/index1.php","http://www.mypage.com/index2.php","http://www.mypage.com/index3.php"])
console.log(urls)

Solution 2

<a href="http://www.mypage.com/index.php?" onclick="this.href+=new Date().getTime();return true;">link</a>

Solution 3

var lower = 0;
var upper = 100000000;
var url = "http://www.mypage.com/index.php?"+(Math.floor(Math.random()*(upper-lower))+lower)

it generates a random X from 0(lower) to 100000000 (upper), you can obv set the bounds you want ;)

Comments

[mplungjan]

document.location is deprecated for document.URL, window.location is what you want here

[Ivo Wetzel]

@mplungjan Just woke up, fixed it :)

[mplungjan]

It will keep adding a new date each time it is clicked. That is why I did a split in my suggestion

[igor]

I thought it's ok for situation with just couple of clicks. If you expect someone to hammer this link, then you have to use split.