hello guys i really need your help.
i have a custom field that i want when the submit button is pressed check my field too . that if it is null
do the same thing that do for the other fields (area of field become red).
ok this is the screenshot of my codes : http://s6.uplod.ir/i/00642/serxinxb1n7y.jpg
and this is the screenshot of my form : http://s6.uplod.ir/i/00642/mstrhiar9pui.jpg
the last label that has text field and drop down ( i specify that with red color in screenshot of my form ) they are my custom fields that you can see it's code in screenshot of my codes
now i want that when i press the submit button check my custom fields that if they are null don't allow the form to be submitted and do the same thing that do for the other fields i mean the area of fields becomes red
( i specify that with yellow highlighter in screenshot of my form ).