Javascript load a random image -

i want create javascript function load random image when function da_image called. want image load onto canvas have set up. there clear error in code? nothing displaying.

var images = [                     "http://circlesfordialogue.com/wp-content/uploads/2014/12/laura-let%c2%b4s-circle-up-2014-12-08.jpg",                     "http://mathworld.wolfram.com/images/eps-gif/concentriccircles_1000.gif",                      "http://www.charlespetzold.com/blog/2012/12/beziercirclefigure3.png"              ];             function da_image(){                 var file = images[0];                  var reader = new filereader();                 reader.onload = function(){                         var img = new image();                         img.src = reader.result;                         img.onerror = function(){                             reset_canvas();                             o.font = '30px sans-serif'                             o.filltext('error: invalid image ' + file.name, 50, 100);                         }                         img.onload = function(){                             document.getelementbyid("text").innerhtml = 'recognizing text... may take while...'                             reset_canvas();                             var rat = math.min(c.width / img.width, c.height / img.height);                             o.drawimage(img, 0, 0, img.width * rat, img.height * rat)                             var tmp = document.createelement('canvas')                             tmp.width = img.width;                             tmp.height = img.height;                             var ctx = tmp.getcontext('2d')                             ctx.drawimage(img, 0, 0)                             var image_data = ctx.getimagedata(0, 0, tmp.width, tmp.height);                             runocr(image_data, true)                         }                      } 

the onload handler triggered when image loaded. when image loaded when set onload handler, doesn't triggered.

so set .src attribute after set .onload function.