上传图片预览

 1//多张图片上传前预览 

function previewFiles() {
  var preview = document.querySelector('#box');
  var files   = document.querySelector('input[type=file]').files
      function readAndPreview(file) {

    // Make sure `file.name` matches our extensions criteria
    if ( /\.(jpe?g|png|gif)$/i.test(file.name) ) {
      var reader = new FileReader();

      reader.addEventListener("load", function () {
        var image = new Image();
        image.src = this.result;
        image.height=85;
        image.width=85;
        image.margin=5;
        image.border= "1px solid #ccc"
        preview.appendChild( image );
      }, false);
      reader.readAsDataURL(file);
    }
  }
  if (files) {
    [].forEach.call(files, readAndPreview);
  }

}