javascript - Function in html and JS is saying its not declared -

my problem getting following console error

uncaught referenceerror: videoarrowminus not defined.

even though defined, wondering if see why not working because stuck.

here js reference in html

<script src="js/postworkout.js"></script> 

here onclick:

onclick="videoarrowminus()" 

and function

function videoarrowminus(){     if(playingvid == 1){             playingvid = 4;             setvideo('videos/week'+ z +'-1.mp4');         } else if (playingvid == 2) {             playingvid = 1;             setvideo('videos/week'+ z +'-2.mp4');         } else if (playingvid == 3) {             playingvid = 2;             setvideo('videos/week'+ z +'-3.mp4');         } else if (playingvid == 4) {             playingvid = 3;             setvideo('videos/week'+ z +'-4.mp4');         } } 

i don't know why it's not working, maybe should try include method invocation inside javascript file (on window load) in following way:

function videoarrowminus(){     if(playingvid == 1){             playingvid = 4;             setvideo('videos/week'+ z +'-1.mp4');         } else if (playingvid == 2) {             playingvid = 1;             setvideo('videos/week'+ z +'-2.mp4');         } else if (playingvid == 3) {             playingvid = 2;             setvideo('videos/week'+ z +'-3.mp4');         } else if (playingvid == 4) {             playingvid = 3;             setvideo('videos/week'+ z +'-4.mp4');         } }  eventlistener(window, 'load', function() {    var element = document.getelementbyid('someid'); // give real name    eventlistener(element, 'click', function() {         videoarrowminus();    }); });  function eventlistener(element, eventname, fn) {     if (element.addeventlistener)         element.addeventlistener(eventname, fn, false);     else if (element.attachevent)         element.attachevent('on' + eventname, fn); }