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

• 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

3 Answers 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.