Web Audio Evaluation Tool

and fails when no <surveryresult> element exist
from analyse.html:

                        root = xml.getElementsByTagName('waetresult')[0];

                        // get subject ID, add to array if not already there
                        pretestSurveyResult = root.getElementsByTagName('surveyresult')[0];
                        subjectID = pretestSurveyResult.getElementsByTagName('comment')[0];
                        if (subjectID){
                            if (subjectID.getAttribute('id')!='sessionId') { // warning in console when not available
                                console.log(xmlFiles[fileIndex]+': no SessionID available');
                            }
                            if (subjectArray.indexOf(subjectID.textContent) == -1) { // if not already in array
                                subjectArray.push(subjectID.textContent); // append to array
                            }
                        }