Drupal6 Small custom hard-coded module for validation

I need a custom module that implements 3 validations for node edit page of "content-type-X" (constant profile type) as below possibly using "jQuery plugin: Validation" or something. <1> When saving the node without having any value in CCK image filed called "field_pic" Show popup alert "You haven't attached any image are you sure you want to continue to save ?" and let the user press OK. <2> When the user is leaving the node edit page "en/user/%/profile/my-content-type" without saving the node. Show popup alert "You haven't saved your content are you sure you want to leave this page?" and let the user press OK. <3>. When saving the node with less than 5 taxonomy child terms attached from either vocabulary A or B (using hierarchical select module) Show popup alert "You should select more terms. Are you sure you want to continue to save ?" and let the user press OK. I don't need UI for the module. You can hard-code and put the content type name,fields, messages,vocabularies directly in the code (I will provide them). If there is alternative way it doesn't have to be "jQuery plugin: Validation" . Thanks.