How do I prevent my dog from jumping out my house window?

The dog is a puppy one year old. It is a collie,jack russell and mixed bread crossed with a mixture of other breads. She is a very busy puppy,cute and small.I have only just found that I can let her off the lead when on the beach and then she will fetch the ball but we have to put on the lead immediately to leave the beach with out having her disappear and cause havoc with other dogs and their families.Please any advice would be appreciated.

close the window, dah!

Training classes will help and more lead walking exercise, also NILIF http://k9aro.webs.com/nilif.htm so you establish leadership

close the window or put her/him in another room

keep it closedtraining

ummm close the window would be a great start.

take her to agility classes collies are the best for it if she is jumping out your window close it but i advise taking her to an agility class

maybe try closing the window