javascript - Partly not responding external prototype-v1.6.0.js file -

javascript - Partly not responding external prototype-v1.6.0.js file -

the next lines in prototype-v1.6.0.js file m using in of jsp files not working. though other statements alert, prompt, etc working. cannot understand issue.please help!!

var fileref=document.createelement('script'); fileref.setattribute("type","text/javascript"); fileref.setattribute("src", "ngcommon.js"); document.getelementsbytagname("head")[0].appendchild(fileref);

javascript jsp