I'm filtering XHTML classes; when there is only a single class it inserts a ma at the beginning. This makes classes that are hidden to have a value ",hidden" which ends up displaying hidden content. What am I missing? No frameworks please, I never use them.

var d = new Array();

for (var i=0;i<c.length;i++)
{
 if (c[i]==c1) {d.push(c2);}
 else if (c[i]==c2) {d.push(c1);}
 else if (c[i]!='') {d.push(c[i]);}
}

d.join(' ');
alert(d);

I'm filtering XHTML classes; when there is only a single class it inserts a ma at the beginning. This makes classes that are hidden to have a value ",hidden" which ends up displaying hidden content. What am I missing? No frameworks please, I never use them.

var d = new Array();

for (var i=0;i<c.length;i++)
{
 if (c[i]==c1) {d.push(c2);}
 else if (c[i]==c2) {d.push(c1);}
 else if (c[i]!='') {d.push(c[i]);}
}

d.join(' ');
alert(d);

• javascript
• split

Share Improve this question Follow edited May 15, 2018 at 8:23 Cœur 38.8k2525 gold badges206206 silver badges278278 bronze badges asked Nov 18, 2011 at 1:55 JohnJohn 13.8k1515 gold badges111111 silver badges192192 bronze badges 1

• 1 Um, you are alerting d and not d.join(' '). Try alerting d.length; I bet it's 2. – Raymond Chen Commented Nov 18, 2011 at 2:04

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3 Answers 3

Sorted by: Reset to default 3

You probably have an Array, of which there is an undefined, null or empty string as the first member, which is having its toString() called somewhere (perhaps implicitly), which calls its join() and the default joiner is the ma (,), resulting in a string with a ma at the start.

>>> [null,'hidden'] + '';
",hidden"

d is still an array after using join(). Store the result of join() in a variable to get the resulting string:

joined=d.join(' ');
alert(joined);

You could use something like:

if (d.length == 1) {
    alert(d[0].substr(1, d[0].length));
}

to clear the first sign.