Adding colomat-close class at certain width

LOVE this plugin.

I’m displaying the collapse/expand trigger <800px wide as I want my sidebar to appear normal and expanded over 800px. However, I want the sidebar to automatically collapse under 800px, so I tried the following jQuery:

function checkWidth(init)
		{
		    /*If browser resized, check width again */
		    if ($(window).width() < 800) {
		        $('#collapse1').removeClass('colomat-close');
		    }
		    else {
		        if (!init) {
		            $('#collapse1').addClass('colomat-close');
		        }
		    }
		}

With the following HTML:

<span class="collapseomatic colomat-close" id="collapse1">Filter</span>
		<span id="swap-collapse1" style="display: none;">Close Filter</span>
		<div class="collapseomatic_content" id="target-collapse1">
			<?php dynamic_sidebar( 'Sidebar' ); ?>
		</div>

But the sidebar just stays expanded even under 800px.

Any ideas?

http://ww.wp.xz.cn/extend/plugins/jquery-collapse-o-matic/