Running jquery script triggered by context menu in chrome extension - google-chrome-extension

Question

I am new to chrome extension development. The sample code I have is not running properly.
Requirement: Executing any jquery script(say $("body").hide();) on click of context menu button.
From the code, only jquery part is not working.
I have following files:
manifest.json
{
"manifest_version": 2,
"name": "jQuery DOM",
"version": "1",
"permissions": [
"contextMenus","tabs","activeTab"
],
"background": {
"scripts": ["jquery.min.js","sample.js"]
},
"description": "Manipulate the DOM when the page is done loading",
"browser_action": {
"name": "Manipulate DOM",
"icons": ["icon.png"],
"default_icon": "icon.png"
},
"content_scripts": [ {
"js": [ "jquery.min.js", "background.js" ],
"matches": [ "http://*/*", "https://*/*"],
"run_at": "document_end"
}]
}
background.js
$("body").append('Test');
I have icon.png in folder, and it gets loaded well.
jquery.min.js in same folder
sample.js
alert("Extension loaded");
function genericOnClick(info, tab) {
alert("Tab "+tab.id);
chrome.tabs.executeScript(tab.id, {
file: "jquery.min.js",
allFrames: true
},function(){
alert("callback");
$("body").hide();
});
alert("Completed");
$("body").hide();
}
var contexts = ["page"];
for (var i = 0; i < contexts.length; i++) {
var context = contexts[i];
var title = "Test Page menu item";
var id = chrome.contextMenus.create({"title": title, "contexts":[context],
"onclick": genericOnClick});
console.log("'" + context + "' item:" + id);
}
background.js works!
All the alerts work file, but .hide function from genericOnClick doesn't work.
Even if I move the code from sample.js to backgroud.js, it won't work.
Can you please tell me where did i go wrong ?

Answer 1

As I mentioned, a background script isn't allowed to interact with the DOM, (while a content script isn't allowed to use chrome.contextMenus). You need to combine both, and use message passing to tell the content script when to execute. Some other adjustments I made:
I renamed background.js and content.js so that their names now
reflect what they do, and made background.js into an event page.
I removed the browser action (the
extension would need browserAction.html or background.js would
need chrome.browserAction.onClicked.addListener to do anything
other than show the icon).
Programmatically injecting jquery means that always loading it as a
content script is unnecessary (although skipping programmatic injection allows you to omit the last three permissions).
background.js doesn't need jquery
anymore, so it isn't loaded there either.
The default executeScript
tab is the active tab, so we don't need it's id.
Here's the finished product:
manifest.json
{
"manifest_version": 2,
"name": "jQuery DOM",
"version": "1",
"permissions": [
"contextMenus", "activeTab", "tabs", "http://*/", "https://*/"
],
"background": {
"scripts": [ "background.js" ],
"persistent": false
},
"content_scripts": [ {
"js": [ "content.js" ],
"matches": [ "<all_urls>" ]
}],
"description": "Manipulate the DOM when the page is done loading"
}
background.js
function genericOnClick(info, tab) {
chrome.tabs.executeScript(null,
{"file": "jquery.min.js"},
function() {
chrome.tabs.sendMessage(tab.id,{"message":"hide"});
});
}
chrome.contextMenus.create({"title": "Test Page menu item",
"contexts":["page"],
"id":"contextId"});
chrome.contextMenus.onClicked.addListener(genericOnClick);
content.js
chrome.runtime.onMessage.addListener(function(msg, sender, sendResponse) {
if (msg.message == 'hide') {
$("body").hide();
}
sendResponse();
});
Your content.js is probably much larger than it is here (+1 for the SSCCE). But if it is small, another option would be to omit the content script entirely, and replace the sendMessage with chrome.tabs.executeScript(null,{code:"$('body').hide();"});.