所以，我有这段代码，下载不会下载此变量。这是代码：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Extension Maker</title>
</head>
<body>
<form>
<h1>Extension maker for chrome</h1>
<input id="name" size="22" placeholder="Extension name">
<br>
<input id="vers" size="22" placeholder="Version">
<br>
<textarea id="desc" placeholder="Description"></textarea>
<br><br><br>
<input type="checkbox" id="popup">Popup <input id="popup-html" placeholder="Popup html">
<br>
<input type="checkbox" id="urlo">Change contents of single page <input id="page-cont" placeholder="Page HTML">
<select id="select">
<option value="newtab">New Tab Page</option>
<option value="bookmarks">Bookmarks Page</option>
<option value="history">History Page</option>
</select>
<br>
<input type="checkbox" id="js">Run JavaScript <input id="js" placeholder="JS">
<br><br><br>
<button onclick="downloadAll()" id="downloadbutton">Download</button>
</form>
<script>
function download(filename, text) {
alert("download script working");
var element = document.createElement('a');
element.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(text));
element.setAttribute('download', filename);
element.style.display = 'none';
document.body.appendChild(element);
element.click();
document.body.removeChild(element);
};
function downloadAll() {
alert("downloadall works!");
var first = document.getElementById("popup").checked;
var second = document.getElementById("urlo").checked;
var third = document.getElementById("js").checked;
var name = document.getElementById("name").value;
var vers = document.getElementById("vers").value;
var desc = document.getElementById("desc").value;
var pophtml = document.getElementById("popup-html").value;
var manifeststart = "{ 'name': " + name + ", 'version': " + vers + ", 'description': " + desc + ", 'manifest_version': 2 ";
if(first === true){
var manifest = manifeststart + "'default_popup': 'popup.html', 'default_icon': { '16': 'images/get_started16.png' } },}";
var text = document.getElementById("popup-html").value;
var filename = "popup.html";
download(filename, text);
};
if(second === true){
var select = var text = document.getElementById("select").value;
var manifest = manifest + "'chrome_url_overrides' : { ' " + select + "': 'myPage.html' }";
var text = document.getElementById("page-cont").value;
var filename = "myPage.html";
download(filename, text);
};
if(third === true){
var manifest = manifest + "'background': {'scripts': ['background.js'],'persistent': false },";
var text = document.getElementById("js").value;
var filename = "background.js";
download(filename, text);
};
var text = manifest;
var filename = "manifest.json";
download(filename, text);
};
</script>
</body>
</html>