I want to use HtmlUnit (v2.21) to get some search result pages from google. This requires me to click on "people also looked for" link when searching for a person (right side, see example link), which triggers some JavaScript and changes the content of the current page. But this gives me an JavaScript Wrapper Exception (see below).
Clickable example link: https://www.google.de/search?ie=UTF-8&safe=off&q=nicki+minaj
Simple TestCase with errors:
String url = "https://www.google.de/search?ie=UTF-8&safe=off&q=nicki+minaj";
WebClient client = new WebClient(BrowserVersion.BEST_SUPPORTED);
HtmlPage page = client.getPage(url);
HtmlElement link = page.getFirstByXPath("//a[#class='_Zjg']");
HtmlPage newPage = link.click(); //throws exception
this.storeResultFile(newPage.asXml(), "test");
client.close();
Result:
net.sourceforge.htmlunit.corejs.javascript.WrappedException: Wrapped java.lang.NullPointerException
at net.sourceforge.htmlunit.corejs.javascript.Context.throwAsScriptRuntimeEx(Context.java:2053)
at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.doProcessPostponedActions(JavaScriptEngine.java:947)
at com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine.processPostponedActions(JavaScriptEngine.java:1012)
at com.gargoylesoftware.htmlunit.html.DomElement.click(DomElement.java:799)
at com.gargoylesoftware.htmlunit.html.DomElement.click(DomElement.java:742)
at com.gargoylesoftware.htmlunit.html.DomElement.click(DomElement.java:689)
I stored the xml of the "page" object and made sure that the XPath expression is valid and has results.
Anybody got any ideas?
Looks like the JavaScript-Engine (based on Rhino) is very easy to upset and quits on some script-issues, where other browsers are still able to run the script.
I dont know if there is a mistake in the scripts from google, but these two lines solved it for me:
JavaScriptEngine engine = client.getJavaScriptEngine();
engine.holdPosponedActions();
Nevertheless, when running multiple htmlunit-objects in multiple threads it is still possible to get accross this error. This is more a workaround than a solution.
I want to preload a large JS file after a page has loaded, so that when I link to that JS file on the required page it is already downloaded and cached.
I'm basically doing this at the moment, and it works, but of course it's not the right way:
preload_js = new Image();
preload_js = "http://domain.com/files/file.js";
This seems such a quick and simple method, no Ajax needed etc. and it works great.
What's the proper way to do this? Surely not with Ajax as that seems overkill for this.
I know there's lots of methods for loading JS but they all seem to actually run the code after the script has loaded, which I don't want.
I don't want to use jQuery (or any library), it must be plain JS. Thanks for any help.
From this blog post:
Preloading components in advance is good for performance. There are
several ways to do it. But even the cleanest solution (open up an
iframe and go crazy there) comes at a price - the price of the iframe
and the price of parsing and executing the preloaded CSS and
JavaScript. There's also a relatively high risk of potential
JavaScript errors if the script you preload assumes it's loaded in a
page different than the one that preloads.
After a bit of trial and lot of error I think I came up with something
that could work cross-browser:
in IE use new Image().src to preload all component types
in all other browsers use a dynamic <object> tag
In this example I assume the page prefetches after onload some
components that will be needed by the next page. The components are a
CSS, a JS and a PNG (sprite).
window.onload = function () {
var i = 0,
max = 0,
o = null,
// list of stuff to preload
preload = [
'http://tools.w3clubs.com/pagr2/<?php echo $id; ?>.sleep.expires.png',
'http://tools.w3clubs.com/pagr2/<?php echo $id; ?>.sleep.expires.js',
'http://tools.w3clubs.com/pagr2/<?php echo $id; ?>.sleep.expires.css'
],
isIE = navigator.appName.indexOf('Microsoft') === 0;
for (i = 0, max = preload.length; i < max; i += 1) {
if (isIE) {
new Image().src = preload[i];
continue;
}
o = document.createElement('object');
o.data = preload[i];
// IE stuff, otherwise 0x0 is OK
//o.width = 1;
//o.height = 1;
//o.style.visibility = "hidden";
//o.type = "text/plain"; // IE
o.width = 0;
o.height = 0;
// only FF appends to the head
// all others require body
document.body.appendChild(o);
}
};
See the post for more details.
EDIT: Looking at the comments on that post, someone mentions this link, which talks about the problems with the new Image() preload method in IE and other browsers. Here's an excerpt:
When IE encounters an IMG tag, it creates an image object and assigns
the download request to it. As data arrives from the image download,
it’s fed into the browser's image decoders. The decoders will reject
data as malformed if you feed them plaintext, which seems reasonable,
since they can't possibly make use of such data. When the decoders
reject the data as "Not possibly an image," the image object will
abort its processing. As a part of that abort, if the download has not
yet completed, it too is aborted.
This explains the behavior mentioned by the OP in the comment below (IE9 only downloading 4KB of the file).
It seems like your only reliable cross-browser option may be to use Ajax...
USE
window.document.onload =function(){
preload_js = "http://domain.com/files/file.js";
}
window.document.onload make sure the java script will not run until you dom is ready
Considering the cross domain issues with Ajax, especially since there really is no way to load a file on a server you have no control over (e.g. Google CDN hosting jQuery), this is my solution:
(1) Use the document.createElement('object') part in Simon M's solution for Firefox as that works great.
(2) Use the new Image.src thing for every other browser. Opera, Safari and Chrome love it. Also, I mentioned earlier that Mobile Safari doesn't work. Well it does, but for some reason takes 100ms verifying something (it is properly cached and it isn't just returning a 304 not modified). I can live with 100ms.
I've not tested other mobile browsers.
(3) Bollocks to IE as nothing works.
i'm writing an greasemonkey script for somebody else. he is a moderator and i am not. and the script will help him do some moderating things.
now the script works for me. as far as it can work for me.(as i am not a mod)
but even those things that work for me are not working for him..
i checked his version of greasemonkey plugin and firefox and he is up to date.
only thing that's really different is that i'm on a mac and he is pc, but i wouldn't think that would be any problem.
this is one of the functions that is not working for him. he does gets the first and third GM_log message. but not the second one ("got some(1) ..").
kmmh.trackNames = function(){
GM_log("starting to get names from the first "+kmmh.topAmount+" page(s) from leaderboard.");
kmmh.leaderboardlist = [];
for (var p=1; p<=(kmmh.topAmount); p++){
var page = "http://www.somegamesite.com/leaderboard?page="+ p;
var boardHTML = "";
dojo.xhrGet({
url: page,
sync: true,
load: function(response){
boardHTML = response;
GM_log("got some (1) => "+boardHTML.length);
},
handleAs: "text"
});
GM_log("got some (2) => "+boardHTML.length);
//create dummy div and place leaderboard html in there
var dummy = dojo.create('div', { innerHTML: boardHTML });
//search through it
var searchN = dojo.query('.notcurrent', dummy).forEach(function(node,index){
if(index >= 10){
kmmh.leaderboardlist.push(node.textContent); // add names to array
}
});
}
GM_log("all names from "+ kmmh.topAmount +" page(s) of leaderboard ==> "+ kmmh.leaderboardlist);
does anyone have any idea what could be causing this ??
EDIT: i know i had to write according to what he would see on his mod screen. so i asked him to copy paste source of pages and so on. and besides that, this part of the script is not depending on being a mod or not.
i got everything else working for him. just this function still doesn't on neither of his pc's.
EDIT2 (changed question): OK. so after some more trial and error, i got it to work, but it's still weird.
when i removed the www-part of the url thats being use in the dojo.xhrGet() i got the finally the same error he got. so i had him add www to his and now it works.
the odd thing is he now uses a script with the url containing "www" and i'm using a script with an url without "www"...
so for me:
var page = "http://somegamesite.com/leaderboard?page="+ p;
and for him:
var page = "http://www.somegamesite.com/leaderboard?page="+ p;
Why don't you have him try logging into an account that is not a moderator account so that you eliminate one of your variables from your problem space.
It's possible that the DOM of the page is different for a moderator than for a regular user. If you're making assumptions about the page as a regular user that are not true as a moderator, that could cause problems.
I suspect that to fix it, you may need access to a moderator account so you can more easily replicate the behavior.
ooops. it seemed that the url of this gamesite is accessible as www.gamesite.com as well as gamesite.com (without the www.part). this caused the problem.
sorry to bother you'all.
i go hide in shame now...
I am very new to javascript so bear with me:
I am trying to replace one quicktime movie with another one, so far i have used this code from apple and it works great
you can see my efforts here: http://www.centurysunstudios.co.uk/test/
please look at the source code (i tried to past the code here but would not let me for some reason; said i could only post one url as a new user? )
the problem is that the replace method apple use works in every browser (on osx and windows) apart from IE. In IE the movies do not replace and i get this message;
Error: document.movie is null or not an object
Apple seem to not have a solution and my javascript is limited
Any help would be greatly appriciated
Thanks
Try this:
<script>
function changeMovie(movieURL){
var embeds = document.getElementsByTagName("embed");
for(var i=0;i<embeds.length;i++){
if(embeds[i].getAttribute("name")=="movie"){
embeds[i].SetURL(movieURL);
}
}
}
</script>
L(o2)
I'm getting a syntax error (undefined line 1 test.js) in Firefox 3 when I run this code. The alert works properly (it displays 'work') but I have no idea why I am receiving the syntax error.
jQuery code:
$.getJSON("json/test.js", function(data) {
alert(data[0].test);
});
test.js:
[{"test": "work"}]
Any ideas? I'm working on this for a larger .js file but I've narrowed it down to this code. What's crazy is if I replace the local file with a remote path there is no syntax error (here's an example):
http://api.flickr.com/services/feeds/photos_public.gne?tags=cat&tagmode=any&format=json&jsoncallback=?
I found a solution to kick that error
$.ajaxSetup({'beforeSend': function(xhr){
if (xhr.overrideMimeType)
xhr.overrideMimeType("text/plain");
}
});
Now the explanation:
In firefox 3 (and I asume only firefox THREE) every file that has the mime-type of "text/xml" is parsed and syntax-checked. If you start your JSON with an "[" it will raise an Syntax Error, if it starts with "{" it's an "Malformed Error" (my translation for "nicht wohlgeformt").
If I access my json-file from an local script - no server is included in this progress - I have to override the mime-type... Maybe you set your MIME-Type for that very file wrong...
How ever, adding this little piece of code will save you from an error-message
Edit: In jquery 1.5.1 or higher, you can use the mimeType option to achieve the same effect. To set it as a default for all requests, use
$.ajaxSetup({ mimeType: "text/plain" });
You can also use it with $.ajax directly, i.e., your calls translates to
$.ajax({
url: "json/test.js",
dataType: "json",
mimeType: "textPlain",
success: function(data){
alert(data[0].test);
} });
getJSON may be insisting on at least one name:value pair.
A straight array ["item0","item1","Item2"] is valid JSON, but there's nothing to reference it with in the callback function for getJSON.
In this little array of Zip codes:
{"result":[["43001","ALEXANDRIA"],["43002","AMLIN"],["43003","ASHLEY"],["43004","BLACKLICK"],["43005","BLADENSBURG"],["43006","BRINKHAVEN"]]}
... I was stuck until I added the {"result": tag. Afterward I could reference it:
<script>
$.getJSON("temp_test_json.php","",
function(data) {
$.each(data.result, function(i, item) {
alert(item[0]+ " " + i);
if (i > 4 ) return false;
});
});
</script>
... I also found it was just easier to use $.each().
This may sound really really dumb, but change the file extension for test.js from .js to .txt. I had the same thing happen with perfectly valid JSON data files with pretty well any extension except .txt (example: .json, .i18n). Since I've changed the extension, I get the data and use it just fine.
Like I said, it may sound dumb but it worked for me.
HI
I have this same error when testing the web page on my local PC, but once it is up on the hosting server the error no longer happens. Sorry - I have no idea of the reason, but thought it may help someone else track down the reason
Try renaming "test.js" to "test.json", which is what Wikipedia says is the official extension for JSON files. Maybe it's being processed as Javascript at some point.
Have you tried disabling all the Firefox extensions?
I usually get some errors in the Firebug console that are caused by the extensions, not by the webs being visited.
Check if there's ; at the end of the test.js. jQuery executes eval("(" + data + ")") and semicolon would prevent Firefox from finding closing parenthesis. And there might be some other unseen characters that prevents it from doing so.
I can tell you why this remote location working though, it's because it's executed in completely different manner. Since it has jsoncallback=? as the part of query parameters, jQuery thinks of it as of JSONP and actually inserts it into the DOM inside <script> tags. Try use "json/test.js?callback=?" as target, it might help too.
What kind of webserver are you running that on? I once had an issue reading a JSON file on IIS because it wasn't defined as a valid MIME type.
Try configuring the content type of the .js file. Firefox expects it to be text/plain, apparently. You can do that as Peter Hoffmann does above, or you can set the content type header server side.
This might mean a server-side configuration change (like apache's mime.types file), or if the json is served from a script, setting the content-type header in the script.
Or at least that seems to have made the error go away for me.
I had a similar problem but was looping through a for loop. I think the problem might be that the index is out of bound.
Kien
For the people who don't use jQuery, you need to call the overrideMimeType method before sending the request:
var r = new XMLHttpRequest();
r.open("GET", filepath, true);
r.overrideMimeType("text/plain");