[英]Convert base64 image to file in javascript or how to pass a big base64 string with jquery ajax
[英]How to convert an image to base64 in JavaScript
我正在尝试编写一个文件上传脚本,用于安全的企业内部网,只是有点麻烦......
在下面的代码中,我没有得到任何错误,我的调试看起来一切正常,但最终结果始终是一个“空白”图像:
var ctx = document.createElement('canvas');
var img = new Image();
img.onload = function(){
ctx.drawImage(img,0,0);
}
img.src = $('#UpdateImage:file');
var imgStr = ctx.toDataURL("image/png", "");
document.getElementById("Item_Create_Image_Avatar").src = imgStr;
当我在'Item_Create_Image_Avatar'对象上“检查元素”时,'src'值看起来绝对完美:
<img src="data:image/png;base64,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" id="Item_Create_Image_Avatar" style="vertical-align:top">
为什么我的图像是空白的?
发现了这个。
Select a File to Load:
<input id="inputFileToLoad" type="file" onchange="loadImageFileAsURL();" />
<div id="imgTest"></div>
<script type='text/javascript'>
function loadImageFileAsURL(){
var filesSelected = document.getElementById("inputFileToLoad").files;
if (filesSelected.length > 0){
var fileToLoad = filesSelected[0];
var fileReader = new FileReader();
fileReader.onload = function(fileLoadedEvent) {
var srcData = fileLoadedEvent.target.result; // <--- data: base64
var divTest = document.getElementById("imgTest");
var newImage = document.createElement('img');
newImage.src = srcData;
divTest.innerHTML = newImage.outerHTML;
}
fileReader.readAsDataURL(fileToLoad);
}
}
</script>
编辑:
如果要在加载后获取图像的数据URL,则应在加载后获取数据URL
var canvas = document.createElement('canvas');
var ctx = canvas.getContext('2d');
var img = new Image();
img.onload = function() {
ctx.drawImage(img, 0, 0);
imgStr = canvas.toDataURL("image/png", "");
document.getElementById("Item_Create_Image_Avatar").src = imgStr;
}
img.src = $('#UpdateImage:file');
编辑:包含其余代码EDIT2:编辑有关画布及其上下文的愚蠢错误
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