Show/Hide Table Rows using Javascript classes

Question

I have a table that kind of expands and collapses, but it's getting too messy to use it and IE and Firefox are not working properly with it.

So, here's the JavaScript code:

  function toggle_it(itemID){ 
      // Toggle visibility between none and '' 
      if ((document.getElementById(itemID).style.display == 'none')) { 
            document.getElementById(itemID).style.display = '' 
            event.preventDefault()
      } else { 
            document.getElementById(itemID).style.display = 'none'; 
            event.preventDefault()
      }    
  } 

And a Sample HTML:

<table>
    <tr>
        <td>Product</td>
        <td>Price</td>
        <td>Destination</td>
        <td>Updated on</td>
    </tr>
    <tr>
        <td>Oranges</td>
        <td>100</td>
        <td><a href="#" id="toggle" onClick="toggle_it('tr1');toggle_it('tr2')">+ On Store</a></td>
        <td>22/10</td>
    </tr>
    <tr id="tr1" style="display:none">
        <td></td>
        <td>120</td>
        <td>City 1</td>
        <td>22/10</td>
    </tr>
    <tr id="tr2" style="display:none">
        <td></td>
        <td>140</td>
        <td>City 2</td>
        <td>22/10</td>
    </tr>
    <tr>
        <td>Apples</td>
        <td>100</td>
        <td><a href="#" id="toggle" onClick="toggle_it('tr3');toggle_it('tr4')">+ On Store</a></td>
        <td>22/10</td>
    </tr>
    <tr id="tr3" style="display:none">
        <td></td>
        <td>120</td>
        <td>City 1</td>
        <td>22/10</td>
    </tr>
    <tr id="tr4" style="display:none">
        <td></td>
        <td>140</td>
        <td>City 2</td>
        <td>22/10</td>
    </tr>
</table>

The problem is that I use one ID for each and every and that's very annoying because I want to have a lot of hidden rows for each parent and a lot of parents, so it would be too many IDs to handle. And IE and FireFox are only showing the first Hidden Row and not the others. I suspect this happens because I've made it work by triggering all IDs together. I think it would be better if I use Classes instead of IDs to indetify the hidden rows.

I'm really new to all of this so please try and explaining it in any kind of simply way. Also I've tried jQuery but wasn't able to get it.

Answer 1

It's difficult to figure out what you're trying to do with this sample but you're actually on the right track thinking about using classes. I've created a JSFiddle to help demonstrate a slightly better way (I hope) of doing this.

Here's the fiddle: link.

What you do is, instead of working with IDs, you work with classes. In your code sample, there are Oranges and Apples. I treat them as product categories (as I don't really know what your purpose is), with their own ids. So, I mark the product <tr>s with class="cat1" or class="cat2".

I also mark the links with a simple .toggler class. It's not good practice to have onclick attributes on elements themselves. You should 'bind' the events on page load using JavaScript. I do this using jQuery.

$(".toggler").click(function(e){
    // you handle the event here
});

With this format, you are binding an event handler to the click event of links with class toggler. In my code, I add a data-prod-cat attribute to the toggler links to specify which product rows they should control. (The reason for my using a data-* attribute is explained here. You can Google 'html5 data attributes' for more information.)

In the event handler, I do this:

$('.cat'+$(this).attr('data-prod-cat')).toggle();

With this code, I'm actually trying to create a selector like $('.cat1') so I can select rows for a specific product category, and change their visibility. I use $(this).attr('data-prod-cat') this to access the data-prod-cat attribute of the link the user clicks. I use the jQuery toggle function, so that I don't have to write logic like if visible, then hide element, else make it visible like you do in your JS code. jQuery deals with that. The toggle function does what it says and toggles the visibility of the specified element(s).

I hope this was explanatory enough.