How to obtain value from single line text box using javascript?

Hi thanks for helping me out. I am trying to obtain the value from a single line text box using this.getTextValue(). What am I doing wrong? Qualtrics.SurveyEngine.addOnReady(function() { /*Place your JavaScript here to run when the page is fully displayed*/ this.questionclick = function(event,element){ //alert('ID: ' +element.id); var answer = this.getTextValue() alert(answer); } });