Here is a relatively simple way to highlight overdue issues… the more overdue they are, the hotter the colour:
There is an overdue custom field plugin – but I didn't want to use that because I needed something without restarting jira. Also this lets you have a gradient for overdue issues, and have different gradients and colours in different contexts (dashboards).
Then create a new portlet of type Text. This is not enabled by default, to enable go to Plugins -> Portlets Plugin -> Text, and click Enable Module.
Download highlightOverdue.js and put in atlassian-jira/includes/js.
Now add a Text portlet to your dashboard.
It should contain:
No restart of jira necessary. Now if that worked, sit back and enjoy glorious technicolor filter results.