do not want to submit form when hit enter

Submitting the form upon enter key press is the standard behavior of any form. Unfortunately it is not possible to change this behavior in our editor.

I would recommend you to enable the "Required" validation of your fields, in that way your form fields wont' be submitted empty:

Another option would be adding a captcha field: http://www.jotform.com/help/205-How-to-Add-a-Captcha

Let us know if  you need more help, we will be glad to assist you.

Good work around. Thanks for the tip.

Just what I needed, thank you!