How can I set an if the query string is does come up as something other than

Question

How can I make a javascript if function where if the query string does show as something other than undefined. Here is the code:

    var getQueryString = window.location.href.split("?")[1];
alert(getQueryString);

Basically I wanted to do an if function in javascript. Here is the code:

    if (getQueryString = 1){
          //add code
    }

How can I set my javascript function?

Im a bit lost, can you elaborate on what you're trying to accomplish — tymeJV, Apr 08 '14 at 19:46
basically if I there is no query string on the url and the alert comes up as undefined I wanted to do an if undefined. — user3499262, Apr 08 '14 at 19:48
Err, undefined is falsy, no need to check for 1 (or set to 1) ? — adeneo, Apr 08 '14 at 19:50
See [link](http://stackoverflow.com/questions/519145/how-can-i-check-whether-a-variable-is-defined-in-javascript) — Always Learning, Apr 08 '14 at 19:52
1. You should not name variables as if they were methods. Verbs should be used for method names only. 2. You are assigning `1` here; for comparison use `==` or `===`. 3. You need to compare against `undefined`; for compatibility and safety (the `undefined` property has not always been read-only), use the `typeof` operator instead. — PointedEars, Apr 08 '14 at 19:52

Bill Criswell · Answer 1 · 2014-04-08T20:17:13.090

1

I would use location.search and check it's length instead of your approach.

if (window.location.search.slice(1).length > 0) {
  doSomething();
}

Currently, your code will always execute because you're setting getQueryString to 1 instead of comparing it. Even if you were comparing it, it would still be false since getQueryString is a string and not a number.

edited Apr 08 '14 at 20:17

answered Apr 08 '14 at 19:48

Bill Criswell

32,161
7
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`location.search` may be `"?"` if there is no query part. Also, it should be `window.location.search`. – PointedEars Apr 08 '14 at 19:54
"May be" does not mean "must be", so in theory you need to trim the leading `?` and then compare the length. Everything is easier with regular expression matching, though. – PointedEars Apr 08 '14 at 19:58
`location.search` returns an empty string even if there's just a `?` at the end of the url. I changed it back to 0. – Bill Criswell Apr 08 '14 at 20:01
1

You are jumping to conclusions. This feature originates from DOM Level 0. There is no specification (that I am aware of), and implementations have been varying over the years. – PointedEars Apr 08 '14 at 20:04
You're totally right. I just tried it in IE9 and it returned just the `?`. I adjusted my code. – Bill Criswell Apr 08 '14 at 20:11
Adjusted. As far as I know it's just a matter of taste, though. – Bill Criswell Apr 08 '14 at 20:18
It is a capital mistake to assume that the ECMAScript Global Object would in general be the same object as the `window` object. And consider local variables. – PointedEars Apr 08 '14 at 23:02

score 0 · Accepted Answer · answered Apr 08 '14 at 19:55

0

The bellow code should work for you

var getQueryString = window.location.href.split("?")[1];

if (typeof getQueryString !== 'undefined')
{
    //Your code goes here
} else [
  alert("Query String not set");
}

answered Apr 08 '14 at 19:55

CGeorges

488
4
16

How can I set an if the query string is does come up as something other than

2 Answers2