insert data in text input field via popup

CKEDITOR.on( 'dialogDefinition', function( ev )
{
var dialogName = ev.data.name;
var dialogDefinition = ev.data.definition;

if ( dialogName == 'image' )
{

var infoTab = dialogDefinition.getContents( 'info' ).elements; //returns the type CKEDITOR.dialog.uiElementDefinition
alert(infoTab[0].children[1].children[0].type);
}}