Change the method of match data-col attribute for exact match

indexOf method is good for whether there is a specific string or not.
But it doesn't work for exact match.

Ex.
```HTML
<li><input type="text" name="" class="filter" data-col="very-good" ></li>
<li><input type="text" name="" class="filter" data-col="good" ></li>
```
```HTML
<tr>
    <th>very-good</th>
    <th>good</th>
</tr>
```
In this case, "good" column doesn't work. 
Because indexOf method can match "good" and "very-good".
So, I change the method for it.
Could you please review this PR if you have time.