call js script in html

1<script type="text/javascript" src="path-to-javascript-file.js"></script>

1<script src="file1.js" type="text/javascript"></script> 
2<script src="file2.js" type="text/javascript"></script> 
3

1<!--if you save the javascript file in a folder-->
2<script type="text/javscript" src="foldername/filename.js"></script>
3<!-- If you save the file in the parent folder-->
4<script type="text/javscript" src="filename.js"></script>

1<script>
2	// JS Here  
3</script>

1function add(param1, param2) {
2    return param1 + param2
3}