Assignment5,function not called

I wrote codes for functions validateInput( )and formSubmission() in scripthelper.js and and called them in script.js. no action is performed. but when I use the same codes in a different computer with index, script and scripthelper files, the code works. I don’t know what needs to be changed. In Firefox browser ,I got the following error, so added to html file. I am frustrated and doing this for the past 4 days. looking badly for help. right now my error is “ReferenceError: formSubmission is not defined at HTMLButtonElement.document.getElementById.onclick (/script.js:23:1)”