[英]How can I display more than one image after uploading several at a time? JS
我正在開發一個圖像管理器,希望通過Google圖像描述進行整理。 目前,我正嘗試一次將所有圖像上傳到服務器並顯示它們,出於某種原因,它僅顯示最后的選擇。
的HTML
<input type='file' accept='image/*' multiple onchange="readURL(this);"/>
<div id="images-container"></div>
<label><strong>(Image will display above)</strong></label>
的CSS
#blah {
display: block;
}
img {
width:100%;
}
.picContainer {
border: 1px dashed black;
margin: 10px;
padding: 10px;
width: 100px;
display: inline-block
}
JS
$("input").change(function(e) {
for (var i = 0; i < e.originalEvent.srcElement.files.length; i++) {
var file = e.originalEvent.srcElement.files[i];
var div = document.createElement("div");
var img = document.createElement("img");
div.className = "picContainer";
var reader = new FileReader();
reader.onloadend = function() {
img.src = reader.result;
}
reader.readAsDataURL(file);
div.appendChild(img);
//$("input").after(div);
var container = document.getElementById("images-container");
container.appendChild(div);
} });
這是因為JavaScript中的變量提升
編譯器將重寫您的代碼,因此它將如下所示:
$("input").change(function(e) {
var i, file, div, img, container;
for (i = 0; i < e.originalEvent.srcElement.files.length; i++) {
file = e.originalEvent.srcElement.files[i];
div = document.createElement("div");
img = document.createElement("img");
div.className = "picContainer";
reader = new FileReader();
reader.onloadend = function() {
img.src = reader.result;
}
reader.readAsDataURL(file);
div.appendChild(img);
//$("input").after(div);
container = document.getElementById("images-container");
container.appendChild(div);
} });
對您來說意味着什么
reader.onloadend = function() {
img.src = reader.result;
}
reader和img變量始終等於最后一個(即使是第一個初始化的變量)
您可能應該使用在循環之前定義的函數創建者,如下所示:
$("input").change(function(e) {
function initOnReaderLoaded(img, reader){
return function(){
img.src = reader.result;
}
}
for (var i = 0; i < e.originalEvent.srcElement.files.length; i++) {
var file = e.originalEvent.srcElement.files[i];
var div = document.createElement("div");
var img = document.createElement("img");
div.className = "picContainer";
var reader = new FileReader();
reader.onloadend = initOnReaderLoaded(img, reader);
reader.readAsDataURL(file);
div.appendChild(img);
//$("input").after(div);
var container = document.getElementById("images-container");
container.appendChild(div);
} });
您必須在閱讀器onload內創建img元素。
在這里擺弄:
function handleFileSelect(evt) {
var files = evt.target.files; // FileList object
// Loop through the FileList and render image files as thumbnails.
for (var i = 0, f; f = files[i]; i++) {
// Only process image files.
if (!f.type.match('image.*')) {
continue;
}
var reader = new FileReader();
// Closure to capture the file information.
reader.onload = (function(theFile) {
return function(e) {
// Render thumbnail.
var span = document.createElement('span');
span.innerHTML = ['<img class="thumb" src="', e.target.result,
'" title="', escape(theFile.name), '"/>'].join('');
document.getElementById('list').insertBefore(span, null);
};
})(f);
// Read in the image file as a data URL.
reader.readAsDataURL(f);
}
}
document.getElementById('files').addEventListener('change', handleFileSelect, false);
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