$(document).ready(function(){

	minheight = 550;  
	height = $('#content_tab').height()+50;
	if (height > 495) {
		if (height < minheight) height = minheight;
		$('#left_tab').height(height);
		$('#content_tab').height(height-50);
	} else {
		height = $('#left_tab').height()-50;
		if (height < minheight) height = minheight;
		$('#content_tab').height(height);
		$('#left_tab').height(height+50);
	}

});