这篇文章给大家分享的是有关js如何实现移动端图片压缩上传功能的内容。小编觉得挺实用的，因此分享给大家做个参考，一起跟随小编过来看看吧。
移动端图片压缩上传功能如何实现？
做移动端开发的时候，form里面的file后台经常获取不到，用foemdata也拿不到
找到了一个formdata的脚本
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0" name="viewport">
<title>移动端图片压缩上传demo</title>
<style>
*{margin: 0;padding: 0;}
li{list-style-type: none;}
a,input{outline: none;-webkit-tap-highlight-color:rgba(0,0,0,0);}
#choose{display: none;}
canvas{width: 100%;border: 1px solid #000000;}
#upload{display: block;margin: 10px;height: 60px;text-align: center;line-height: 60px;border: 1px solid;border-radius: 5px;cursor: pointer;}
.touch{background-color: #ddd;}
.img-list{margin: 10px 5px;}
.img-list li{position: relative;display: inline-block;width: 100px;height: 100px;margin: 5px 5px 20px 5px;border: 1px solid rgb(100,149,198);background: #fff no-repeat center;background-size: cover;}
.progress{position: absolute;width: 100%;height: 20px;line-height: 20px;bottom: 0;left: 0;background-color:rgba(100,149,198,.5);}
.progress span{display: block;width: 0;height: 100%;background-color:rgb(100,149,198);text-align: center;color: #FFF;font-size: 13px;}
.size{position: absolute;width: 100%;height: 15px;line-height: 15px;bottom: -18px;text-align: center;font-size: 13px;color: #666;}
.tips{display: block;text-align:center;font-size: 13px;margin: 10px;color: #999;}
.pic-list{margin: 10px;line-height: 18px;font-size: 13px;}
.pic-list a{display: block;margin: 10px 0;}
.pic-list a img{vertical-align: middle;max-width: 30px;max-height: 30px;margin: -4px 0 0 10px;}
</style>
</head>
<body>
<input type="file" id="choose" accept="image
function getBlob(buffer, format) {
try {
return new Blob(buffer, {type: format});
} catch (e) {
var bb = new (window.BlobBuilder || window.WebKitBlobBuilder || window.MSBlobBuilder);
buffer.forEach(function(buf) {
bb.append(buf);
});
return bb.getBlob(format);
}
}
function getFormData() {
var isNeedShim = ~navigator.userAgent.indexOf('Android')
&& ~navigator.vendor.indexOf('Google')
&& !~navigator.userAgent.indexOf('Chrome')
&& navigator.userAgent.match(/AppleWebKit\/(\d+)/).pop() <= 534;
return isNeedShim ? new FormDataShim() : new FormData()
}
function FormDataShim() {
console.warn('using formdata shim');
var o = this,
parts = [],
boundary = Array(21).join('-') + (+new Date() * (1e16 * Math.random())).toString(36),
oldSend = XMLHttpRequest.prototype.send;
this.append = function(name, value, filename) {
parts.push('--' + boundary + '\r\nContent-Disposition: form-data; name="' + name + '"');
if (value instanceof Blob) {
parts.push('; filename="' + (filename || 'blob') + '"\r\nContent-Type: ' + value.type + '\r\n\r\n');
parts.push(value);
}
else {
parts.push('\r\n\r\n' + value);
}
parts.push('\r\n');
};
// Override XHR send()
XMLHttpRequest.prototype.send = function(val) {
var fr,
data,
oXHR = this;
if (val === o) {
// Append the final boundary string
parts.push('--' + boundary + '--\r\n');
// Create the blob
data = getBlob(parts);
// Set up and read the blob into an array to be sent
fr = new FileReader();
fr.onload = function() {
oldSend.call(oXHR, fr.result);
};
fr.onerror = function(err) {
throw err;
};
fr.readAsArrayBuffer(data);
// Set the multipart content type and boudary
this.setRequestHeader('Content-Type', 'multipart/form-data; boundary=' + boundary);
XMLHttpRequest.prototype.send = oldSend;
}
else {
oldSend.call(this, val);
}
};
}
</script>
</body>
</html>感谢各位的阅读！关于“js如何实现移动端图片压缩上传功能”这篇文章就分享到这里了，希望以上内容可以对大家有一定的帮助，让大家可以学到更多知识，如果觉得文章不错，可以把它分享出去让更多的人看到吧！
