CRM 2011 Javascript Expert

Hello to all. We are looking for a Javascript Expert in CRM 2011. We have tried a little CRM 2011 and we saw about the javascript events like onload, onchange, etc. We need an expert that can provide us the specific CRM javascript for the points that you will find below and assist us during the installation and configuration of this codes in crm. 1. Clear fields with the onload event. We need some javascript to add to the onload event that clears some fields. These fields are: a date and some dropdown fields. 2. Show/Hide fields based on the choices made in other fields. We want to show or hide some fields based on the choices made in a dropdown field so we need a javascript for the onchange event of that field. 3. We need a javascript for the onchange event that based on a choice made in a dropdown, it populates one or many other dropdowns with predefined choices that we can decide. So for example if in the first dropdown I choose “Bread” in the second dropdown the field “Food” will be automatically chosen. 4. We have a dropdown with many choices. There is one choice from this dropdown that is important and needs some javascript to do the following: We want to make another dropdown field visible ONLY when we go away from this choice. This means that If this choice was previously choosen during the creation or the update of a lead, then when updating again the lead, if someone changes from this choice to another , this is when the hidden field has to be visible.