【发布时间】：2016-05-26 04:12:01
【问题描述】：
我正在制作一个 chrome 扩展来更改新标签的背景图像。第一次加载扩展时，背景图像不会改变。
这个问题也非常偶尔在长时间使用后出现（但我不确定它在什么时候不起作用，除非在第一次安装时）。谢谢。
main.js
/*THIS CODE IS FOR GETTING THE NUMBER OF IMAGES FROM PHP*/
// INCLUDE JQUERY LIBRARY: OTHERWISE THIS WON'T WORK...
// SURE YOU CAN ALSO DO ALL THESE IN PURE JAVASCRIPT, BUT WHY RE-INVENT THE WHEEL? :-)
(function ($) {
$(document).ready(function(e) {
$.ajax({
url: 'http://url.com/numberOfImages.php', // <== CHANGE URL
dataType: "HTML",
cache: false,
type: "POST",
//HANDLE THE SUCCESS CASE FOR THE AJAX CALL
success: function (data, textStatus, jqXHR) {
if(data){
localStorage.numberOfImages = data;
gotNumberOfImages = true;
}
},
//HANDLE THE FAILURE CASE FOR THE AJAX CALL
error: function (jqXHR, textStatus, errorThrown) {
console.log('The following error occurred: ' + textStatus, errorThrown);
},
//HANDLE THE EVENT-COMPLETE CASE FOR THE AJAX CALL
complete: function (jqXHR, textStatus) {
}
});
});
})(jQuery);
window.onload = function() {
showNewImage();
var str = document.getElementById("greet").innerHTML;
var res = str.replace("\'\'", " " + localStorage.name); // replace with name
document.getElementById("greet").innerHTML = res;
};
// Set up the image files to be used.
var theImages = new Array() // do not change this
// To add more image files, continue with the
// pattern below, adding to the array.
var numberOfImages;
if (navigator.onLine) { //checking if connected to internet, if it finds the user is online it'll call the images that are on the server.
for(i = 0; i<=localStorage.numberOfImages;i++){
theImages[i] = 'http://url.com/images/'+ i +'.jpg'; //NAME THE IMAGES ON THE SERVER 0.JPG, 1.JPG, 2.JPG and so on.
}
} else { //if offline, if it finds that the user is offline it'll use these images. REMEMBER TO PUT A FEW OF THESE.
theImages[0] = 'image3.jpg'
theImages[1] = 'image4.jpg'
}
var j = 0
var p = theImages.length;
var preBuffer = new Array()
for (i = 0; i < p; i++){
preBuffer[i] = new Image()
preBuffer[i].src = theImages[i]
}
var whichImage = Math.round(Math.random()*(p-1));
function showNewImage(){
document.body.style['background-image'] = 'url("' + theImages[whichImage] + '")';
//localStorage.img = theImages[whichImage];
}
manifest.json
{
"name": "App name",
"description": "Add description",
"version": "1.0",
"permissions": [
"activeTab"
],
"chrome_url_overrides" : {
"newtab": "main.html"
},
"background": {
"scripts": ["jquery-2.2.3.min.js"],
"persistent": false
},
"permissions": [
"activeTab",
"https://ajax.googleapis.com/",
"storage",
"tabs",
"http://*/*",
"https://*/*"
],
"browser_action": {
"default_title": "some title"
},
"manifest_version": 2
}
main.html
<html>
<head>
<title>New Tab</title>
<link rel="stylesheet" href="main.css">
<link rel="stylesheet" href="/octicons/octicons.css">
<meta name="viewport" content="width=device-width, initial-scale=1">
<script src="jquery-2.2.3.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.3/jquery.min.js"></script>
</head>
<body>
...
<script src = "main.js"></script>
</body>
</html>
【问题讨论】：
标签： javascript css google-chrome google-chrome-extension