finding and replacing parameters in href with javascript

Question

Here's the issue:

I need to check for a parameter in the query. If it's been set, then I need to change it (harder part). If it hasn't been set, I need to set it (easy part)

I was so sure it would be an easy task, but it somehow ended up being a bit more complicated than I thought. Especially for those cases where there are multiple parameters, and the one I'm looking for is in the middle somewhere.

The parameter is "siteLanguage", and is always followed by =xx where xx represents any two characters, like en or es or whatever. So maybe regex is the answer (boy, do I suck at regex)

No frameworks for this one, guys, just plain ol' javascript.

The href of the page runing the js, or the href of links on the page? — Eric
– Eric, Commented Oct 1, 2009 at 14:06

Aaron Digulla · Accepted Answer · 2009-10-01 14:13:49Z

2

I guess you've figured out how to find all the links.

The standard format of an URL is service://host/path?query

I suggest to cut away the query (just take everything after the first ?) and then split that at & (because that separates parameters).

You'll be left with an array of the form key=value. Split that into an associative array. Now you can work on that array. After you've made your modifications, you need to join the query again and set the href attribute of the link.

answered Oct 1, 2009 at 14:13

Aaron Digulla

330k111 gold badges626 silver badges840 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

peirix Over a year ago

That sounds pretty waterproof. But a bit too complicated when only looking for one parameter, and even knowing the name of it. This would be better for a general function, though, I think.

Mark · Accepted Answer · 2009-10-01 14:25:49Z

1

This would check all "a href=" throughout the document appending or adjusting the language.

checkhrefs = function(lang){
        var links = document.getElementsByTagName("a");
        for (var i=0;i<links.length;i++){
            if (links[i].href.indexOf("siteLanguage") == -1){
                links[i].href += "&siteLanguage="+lang;
            } else {
                links[i].href = links[i].href.replace(new RegExp("siteLanguage=[a-z][a-z]"),"siteLanguage="+lang);
            }
        }
    }

answered Oct 1, 2009 at 14:25

Mark

109k20 gold badges180 silver badges238 bronze badges

1 Comment

peirix Over a year ago

Hehe. No, but I do like your regex. Which might be quicker than doing indexOf + substring + replace...

peirix · Accepted Answer · 2009-10-05 11:37:46Z

0

Ended up just doing a quick hack like so:

function changeLanguage(lang) {
   if (location.search.indexOf("siteLanguage") > -1) { //siteLanguage set
      location.href = location.search.replace(/siteLanguage=[a-z][a-z]/, "siteLanguage="+lang);
   } else if (location.search == "") {
      location.href += "?siteLanguage="+lang;
   } else {
      location.href += "&siteLanguage="+lang;
   }
}

Actually pretty happy with a 9-liner function...

answered Oct 5, 2009 at 11:37

peirix

37.9k24 gold badges98 silver badges130 bronze badges

Collectives™ on Stack Overflow

finding and replacing parameters in href with javascript

3 Answers 3

1 Comment

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related