<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<title>File API Test</title>
<script type="text/javascript" src="jquery-1.11.0.min.js"></script>
<script type="text/javascript" src="de.js"></script>
<style>
#test{
100px;
height:100px;
}
</style>
</head>
<body>
<input type="file" id="fileImg" >
<form>
<img src="" id="test" alt="">
</form>
<script>
function handleFileSelect (evt) {
console.log( document.getElementById("fileImg").files);
// var filebtn = document.getElementById(id);
// console.log(filebtn);
// var files = filebtn.target.files;
// console.log(filebtn.target);
// console.log(files);
var files = evt.target.files;
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.
// console.log(evt.target.files[0]);
// console.log(e.target);
console.log(e.target.result);
var i = document.getElementById("test");
i.src = event.target.result;
console.log($(i).width());
console.log($(i).height());
$(i).css('width',$(i).width()/10+'px');
//$(i).css('height',$(i).height()/10+'px');
console.log($(i).width());
console.log($(i).height());
var quality = 50;
i.src = jic.compress(i,quality).src;
console.log(i.src);
i.style.display = "block";
};
})(f);
// Read in the image file as a data URL.
reader.readAsDataURL(f);
}
}
document.getElementById('fileImg').addEventListener('change', handleFileSelect, false);
</script>
</body>
</html>
de.js
var jic = { /** * Receives an Image Object (can be JPG OR PNG) and returns a new Image Object compressed * @param {Image} source_img_obj The source Image Object * @param {Integer} quality The output quality of Image Object * @return {Image} result_image_obj The compressed Image Object */ compress: function(source_img_obj, quality, output_format){ var mime_type = "image/jpeg"; if(output_format!=undefined && output_format=="png"){ mime_type = "image/png"; } var cvs = document.createElement('canvas'); //naturalWidth真实图片的宽度 cvs.width = source_img_obj.naturalWidth; cvs.height = source_img_obj.naturalHeight; var ctx = cvs.getContext("2d").drawImage(source_img_obj, 0, 0); var newImageData = cvs.toDataURL(mime_type, quality/100); var result_image_obj = new Image(); result_image_obj.src = newImageData; return result_image_obj; }, function (){} }
这是在网上摘抄的完整代码，可以直接运行成功。