Validate field value by javascript before submitting an item

Please give one example of select & text. In my case, I dont want to validate values of fields, I only want to check if group of some field is blank or not.

In my form
There is group of 4 select field & one text box. I want to check if all of select fields and text field have blank, then form should not be submitted.

Hello

enable the "Required" parameter inside editing TAB