我想改变按钮上的默认文本，即“选择文件”，当我们使用input=" File"。
我该怎么做呢?也可以看到，在图像按钮是在文本的左侧。我怎么把它放在文本的右边?
当前回答
使用Bootstrap你可以像下面的代码一样做这件事。
<!DOCTYPE html>
<html lang="en">
<head>
<style>
.btn-file {
position: relative;
overflow: hidden;
}
.btn-file input[type=file] {
position: absolute;
top: 0;
right: 0;
min-width: 100%;
min-height: 100%;
font-size: 100px;
text-align: right;
filter: alpha(opacity=0);
opacity: 0;
outline: none;
background: white;
cursor: inherit;
display: block;
}
</style>
<title>Bootstrap Example</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
</head>
<body>
<span class="btn btn-file">Upload image from here<input type="file">
</body>
</html>
其他回答
诀窍是在点击文件输入时触发一个点击事件，并通过CSS管理默认输入文件的可见性。你可以这样做: jQuery:
$(function() {
$("#labelfile").click(function() {
$("#imageupl").trigger('click');
});
})
css
.file {
position: absolute;
clip: rect(0px, 0px, 0px, 0px);
display: block;
}
.labelfile {
color: #333;
background-color: #fff;
display: inline-block;
margin-bottom: 0;
font-weight: 400;
text-align: center;
vertical-align: middle;
cursor: pointer;
background-image: none;
white-space: nowrap;
padding: 6px 8px;
font-size: 14px;
line-height: 1.42857143;
-webkit-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
user-select: none;
}
HTML代码:
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<div>
<input name="imageupl" type="file" id="imageupl" class="file" />
<label class="labelfile" id="labelfile"><i class="icon-download-alt"></i> Browse File</label>
</div>
这是不可能的。否则，你可能需要使用Silverlight或Flash上传控件。
这里是如何用bootstrap完成的，只是你应该把原始输入放在某个地方…idk 在头部，如果你有< br >，删除它，因为它只是隐藏和占用空间:)
<head> <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous"> </head> <label for="file" button type="file" name="image" class="btn btn-secondary">Secondary</button> </label> <input type="file" id="file" name="image" value="Prebrskaj" style="visibility:hidden;"> <footer> <script src="https://code.jquery.com/jquery-3.4.1.slim.min.js" integrity="sha384-J6qa4849blE2+poT4WnyKhv5vZF5SrPo0iEjwBvKU7imGFAV0wwj1yYfoRSJoZ+n" crossorigin="anonymous"></script> <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js" integrity="sha384-wfSDF2E50Y2D1uUdj0O3uMBJnjuUD4Ih7YwaYd1iqfktj0Uod8GCExl3Og8ifwB6" crossorigin="anonymous"></script> </footer>
$(document).ready(function () { $('#choose-file').change(function () { var i = $(this).prev('label').clone(); var file = $('#choose-file')[0].files[0].name; $(this).prev('label').text(file); }); }); .custom-file-upload{ background: #f7f7f7; padding: 8px; border: 1px solid #e3e3e3; border-radius: 5px; border: 1px solid #ccc; display: inline-block; padding: 6px 12px; cursor: pointer; } <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> can you try this <label for="choose-file" class="custom-file-upload" id="choose-file-label"> Upload Document </label> <input name="uploadDocument" type="file" id="choose-file" accept=".jpg,.jpeg,.pdf,doc,docx,application/msword,.png" style="display: none;" />
Below is an example of a stylized upload button that will read an image, compress it, and download the resulting image. It works by hiding the actual input element, and then through some trickery we make it so that when you click on our fake file uploader it uses the actual input element to pop up the window for choosing a file. By using this method we get 100% control over how the file uploader looks since we are using our own element instead of styling the file upload menu. It also makes it easy to add drag and drop functionality in the future if we ever want to do that.
然后我写了一系列关于这个文件上传按钮的博文。
'use strict' var AMOUNT = 10 var WIDTH = 600 var HEIGHT = 400 var canvas = document.getElementById('canvas') canvas.width = WIDTH canvas.height = HEIGHT //here's how I created the clickable area //user clicks the clickable area > we send a click event //to the file opener > the file opener clicks on the open //file button > the open file dialogue pops up function clickableAreaListener(e){ let clickEvent = new CustomEvent("click",{"from":"fileOpenerHandler"}); document.getElementById("fileOpener").dispatchEvent(clickEvent); } function fileOpenerListener(e) { document.getElementById("file-btn").click(); e.preventDefault(); } function fileSelectedListener(e){ readFiles(e.target.files); } document.getElementById('file-btn').addEventListener('change', fileSelectedListener); document.getElementById("clickable-area").addEventListener('click', clickableAreaListener); document.getElementById("fileOpener").addEventListener("click", fileOpenerListener); function readFiles(files){ files = [].slice.call(files); //turning files into a normal array for (var file of files){ var reader = new FileReader(); reader.onload = createOnLoadHandler(file); reader.onerror = fileErrorHandler; //there are also reader.onloadstart, reader.onprogress, and reader.onloadend handlers reader.readAsDataURL(file); } } function fileErrorHandler(e) { switch(e.target.error.code) { case e.target.error.NOT_FOUND_ERR: throw 'Image not found'; break; case e.target.error.NOT_READABLE_ERR: throw 'Image is not readable'; break; case e.target.error.ABORT_ERR: break; default: throw 'An error occurred while reading the Image'; }; } function createOnLoadHandler(file){ console.log('reading ' + file.name + ' of type ' + file.type) //file.type will be either image/jpeg or image/png function onLoad(e){ var data = e.target.result display(data); var compressedData = compressCanvas(AMOUNT) download(compressedData) } return onLoad } function display(data){ var img = document.createElement('img'); img.src = data; var context = canvas.getContext('2d') context.clearRect(0, 0, WIDTH, HEIGHT); context.drawImage(img, 0, 0, WIDTH, HEIGHT); } function compressCanvas(){ return canvas.toDataURL('image/jpeg', AMOUNT / 100); } function download(data) { function b64toBlob(b64Data, contentType, sliceSize) { contentType = contentType || ''; sliceSize = sliceSize || 512; var byteCharacters = atob(b64Data); var byteArrays = []; for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) { var slice = byteCharacters.slice(offset, offset + sliceSize); var byteNumbers = new Array(slice.length); for (var i = 0; i < slice.length; i++) { byteNumbers[i] = slice.charCodeAt(i); } var byteArray = new Uint8Array(byteNumbers); byteArrays.push(byteArray); } var blob = new Blob(byteArrays, {type: contentType}); return blob; } var chromeApp = Boolean(chrome && chrome.permissions) if (chromeApp){ chrome.fileSystem.chooseEntry({type:'openDirectory'}, function(entry) { chrome.fileSystem.getWritableEntry(entry, function(entry) { entry.getFile('example.jpg', {create:true}, function(entry) { entry.createWriter(function(writer){ writer.write(b64toBlob(data.slice(23), 'image/jpg')) }) }) }) }) } else { let a = document.createElement("a"); a.href = data; a.download = 'downloadExample.jpg' document.body.appendChild(a) a.click(); window.URL.revokeObjectURL(a.href); a.remove() } } .fileInput { display: none; position: absolute; top: 0; right: 0; font-size: 100px; } #clickable-area{ background: #ccc; width: 500px; display: flex; margin-bottom: 50px; } #clickable-area-text{ margin: auto; } .yellow-button { cursor: pointer; color: white; background: #f1c40f; height: 30px; width: 120px; padding: 30px; font-size: 22px; text-shadow: 0 1px 2px rgba(0, 0, 0, 0.25); } <div id="clickable-area"> <a id='fileOpener'> </a> <input type="file" class="fileInput" id="file-btn" accept="image/*" multiple/> <div class="yellow-button"><span>Shrink Image</span> </div><p id="clickable-area-text">( you can click anywhere in here ) </p> </div> <canvas id="canvas"></canvas>
Stack Overflow的限制似乎阻止了代码片段实际压缩和下载文件。这里完全相同的代码显示了完整的上传/压缩/下载过程实际上按预期工作。
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