I’m not legally allowed to take my kids away from their father’s jurisdiction

my husband has made me sign a document which says that I’m not legally allowed to take my kids away from their father’s jurisdiction and that happened when i left my kids at my husband’s place in anger for a couple of days..he and his family then took advantage of that when i begged them to come and see my kids but they let me come on this condition if i sign that said document…one of my daughters is 5 years old…i want to ask that can i have my kids custody if he has that document.