Concatenate Strings in JavaScript

Question

I Have edited the code, the updated code is below, This code is not able to fetch the keywords meta tag, hence it is not working.

old description: I am trying to concatinate the strings to get the finalUrl, but I am not able to do so becuase of the tags variable. I need to fetch the keywords meta tag of the page and append it to get the finalUrl. Any help?

  <script type="text/javascript">


    var tags=$('meta[name=keywords]').attr("content");
    var gameurl = "http://xyz/abc/details/";
    var jsn = ".json?callback=showGameDetail";
    var finalUrl= gameurl.concat(tags).concat(jsn);


function loadJSON(url) {
  var headID = document.getElementsByTagName("head")[0];
  var newScript = document.createElement('script');
      newScript.type = 'text/javascript';
      newScript.src = url;
  headID.appendChild(newScript);
}

function showGameDetail(feed){
  var title = feed.title;



    var game_url = feed.pscomurl;
    var packart_url = feed.Packart;
  $("#bnr-ads-box").html("<img src='"+"http://abc.com/"+packart_url+"'>");




}

loadJSON(finalUrl);
</script>
<div id="bnr-ads-box"></div>

Use a plus: var finalUrl = gameurl + tags + jsn; - It is very googlable using string concatenation to get to MDN — mplungjan
– mplungjan, Commented Aug 26, 2013 at 8:31
If you are trying to evaluate the output of the jquery script you should not put it inside quote. Directly right var tags=$('meta[name=keywords]').attr("content"); — Subir Kumar Sao
– Subir Kumar Sao, Commented Aug 26, 2013 at 8:35
I am sure you are missing tags var value here. Always debug whether you are getting right value if you gonna use it later — Akki619
– Akki619, Commented Aug 26, 2013 at 8:35
What is the out put of tags if you print it in console. console.debug(tags). Post the output data structure. — Subir Kumar Sao
– Subir Kumar Sao, Commented Aug 26, 2013 at 8:39

Leo T Abraham · Accepted Answer · 2013-08-26 09:23:00Z

1

<!DOCTYPE html>
<html>
    <head>
        <meta id="metaK" name="keywords" content="customizable software for QuickBooks, QuickBooks-integrated, Method customization, CRM accounting, Method for QuickBooks, Method CRM, Method blog,  Salesforce automation, Method online platform, QuickBooks customization, web-based platform, industry-specific, customer portal, Method Field Services, Method Manufacturing, ERP" />
        <script type="text/javascript" src="http://code.jquery.com/jquery-1.10.2.min.js"></script>
    </head>
<body>

<p id="demo">Click the button to join two strings into one new string.</p>

<button onclick="myFunction()">Try it</button>

<script>
function myFunction()
{
var tags=$('meta[name=keywords]').attr("content");

var gameurl = "http://xyz/abc/names/";
var jsn = ".json?callback=showGameDetail";
var finalUrl= gameurl.concat(tags).concat(jsn);

document.getElementById("demo").innerHTML=finalUrl;
}
</script>

</body>

</html>

edited Aug 26, 2013 at 9:23

answered Aug 26, 2013 at 8:31

Leo T Abraham

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2 Comments

Varun Luthra Over a year ago

Doesn't work when var tags= $('meta[name=keywords]').attr("content"); Works if the value of tags is simple, lets say var tags = "name_of_page"

Varun Luthra Over a year ago

In my string "tags", let say I am getting following output Keyword1, Keyword2, Keyword3, keyword4 but i need to use on Keyword1 to use in my finalUrl to make the URL, how to achieve it.

Cris · Accepted Answer · 2013-08-26 08:33:50Z

1

change this

var tags="$('meta[name=keywords]').attr("content");";

to

var tags=$('meta[name=keywords]').attr("content");

also use this code var finalUrl = gameurl + tags + jsn;

answered Aug 26, 2013 at 8:33

Cris

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Comments

Christian · Accepted Answer · 2013-08-26 08:44:21Z

1

What you need is to escape the double quotes inside your tags variable, like so:

var tags="$('meta[name=keywords]').attr(\"content\");";

Cris' solution is also fine, but in some case you will need to have two sets of double quotes inside a string so you will be forced to do escaping correctly.

FYI: Escaping is the process of having special characters getting generated in a string which would otherwise cause issues, for instance in javascript you can't have newlines in a string, like this:

var mystring = 'on
a different line'; // <- this causes a syntax error

So one would do the following:

var mystring = 'on\na different line';

answered Aug 26, 2013 at 8:44

Christian

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3 Comments

mplungjan Over a year ago

See my answer which is using encodeURIComponent to avoid that

Christian Over a year ago

Actually, @mplungjan covered more stuff than mine - but it lacks some explaining. :)

mplungjan Over a year ago

Updated while you commented :)

Brij Raj Singh - MSFT · Accepted Answer · 2013-08-26 08:52:56Z

1

You forgot to include the jquery

<!DOCTYPE html>
<html>
<head>
<meta name="keywords" content="hello"/>

<script type="text/javascript" src="http://code.jquery.com/jquery-1.10.2.min.js"></script>
<script type="text/javascript">
function myFunction()
{
alert("Hello World!");
var tags=$('meta[name=keywords]').attr("content");

var gameurl = "http://xyz/abc/names/";
var jsn = ".json?callback=showGameDetail";
var finalUrl= gameurl.concat(tags).concat(jsn);
alert(finalUrl);
}
</script>
</head>

<body>
<button onclick="myFunction()">Try it</button>
</body>
</html>

answered Aug 26, 2013 at 8:52

Brij Raj Singh - MSFT

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Comments

roland · Accepted Answer · 2015-04-16 16:58:10Z

1

Tough debatable, you can use an array, which can be concatenated by calling join():

var tags = $('meta[name=keywords]').attr("content");
var data = [
 "http://xyz/abc/names/",
 encodeURIComponent(tags),
 ".json?callback=showGameDetail"
].join('');
$("#demo").html(data);

edited Apr 16, 2015 at 16:58

answered Aug 26, 2013 at 8:47

roland

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4 Comments

mplungjan Over a year ago

Euuw. At least push the strings if you want to use an array

Christian Over a year ago

This is a very elegant solution than having all the stuff on one line. A different and elegant way would be to have the different strings in properly named variables:

var url = "http://xyz/abc/names/", query = ".json?callback=showGameDetail"; var data = url + encodeURIComponent(tags) + query;

mplungjan Over a year ago

I do not see the elegance over having + in this particular example - it adds unnecessary [].join("")

roland Over a year ago

No need to use push() as an array can be initialized directly. Besides it would be overkill to use push() if the main goal is to produce a string.

mplungjan · Accepted Answer · 2013-08-26 09:01:21Z

0

Actually the concat method works on strings too (in chrome at least) but the recommended method is using the plus concatenation string operator

You are however missing some stuff

jQuery library - I assume you want that since you have $(...) in the example
encoding of the string from the keywords - I use encodeURIComponent to handle possible newlines and quotes in the keywords

.

<!DOCTYPE html>
<html>
<head>
    <title>Create a URL from keywords</title>
    <meta name="keywords" content="These are tags" />
    <script src="http://code.jquery.com/jquery-1.10.2.min.js"></script>
    <script>
    function myFunction() {
      var tags = $('meta[name=keywords]').attr("content");
      var URL ="http://xyz/abc/names/" +
       encodeURIComponent(tags) + 
       ".json?callback=showGameDetail";
      window.console &&  console.log(URL);
      $("#demo").html(URL);     
   }
   </script>
  <body>
    <p id="demo">Click the button to join two strings into one new string.</p>
    <button onclick="myFunction()">Try it</button>
  </body>
</html>

edited Aug 26, 2013 at 9:01

answered Aug 26, 2013 at 8:39

mplungjan

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2 Comments

Christian Over a year ago

The question was misusing (actually, missing) the concept of string-escaping. I would cover this as well in my answer (as I already did) - at least for the sake of learning.

mplungjan Over a year ago

Is someone on a downvoting spree here? Why is this downvoted without comment?

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