Develop Reference

Execute command on another tab

I'm new at JavaScript, so can someone help me? How can I execute a command on another tab? For example, I have opened new tab from my main tab and opened translate.com (just for textbox) on it, and the problem is I don't know how to put text in search textbox?
I open the page with this command:
var page = window.open('https://www.translate.com/');
On the page, I can enter text with this code:
$string1 = $("#source_text");
$string1.val("text");
I have tried this, but this code doesn't work the way I want it to.
var page = window.open('https://www.translate.com/');
setTimeout(function(){page.f1()},20000);
setTimeout(function(){page.close()},30000);
function f1() {
$string1 = $("#source_text");
$string1.val("ka tu");
}

I find the function that you are trying to run very abnormal. So, let's start with small steps.
The page.close() function is perfect you can do that and it works. The other part won't work first of all because the page object created by window.open has no function called f1 on it.
Furthermore it is very important from where you are trying to run the script on the other window you always must take into consideration the cross-origin limitations. Easily explained if you try to run a function from a google.com tab on a separate window yahoo.com it won't work this is a security issue.
In order to run function f1 in that window it is important that f1 function is declared globally and ussualy you try and do this the following way page.window.f1() - and there you have it. So for example your code would be
page.window.$("#source_text").val('something');
refactoring your code would be like this:
var page = window.open('https://www.translate.com/');
setTimeout(function(){ page.window.$("#source_text").val('something');},20000);
setTimeout(function(){page.close()},30000);
open translate.com in a tab open dev tools in chrome and paste the above code in the console tab and see the results, it will work.
I recommend that before running code in another window you should check that that window is loaded first of all (in your case works) because of the long timeout.
A better solution would be using HTML5's postMessage API: check this link here for a good tutorial: https://robertnyman.com/2010/03/18/postmessage-in-html5-to-send-messages-between-windows-and-iframes/ - also this meens of course that the window you are opening is listening for some sort of postMessages.
In general you do this things with hosts that you manage and not other hosts because it might not work always. Also it will always work if you are on a host and open the same host in another window otherwise you end up with this security error: VM88:2 Uncaught SecurityError: Blocked a frame with origin "https://some_other_host" from accessing a frame with origin "https://www.translate.com". Protocols, domains, and ports must match.
Hope this helps, and you understand the way it works now.
Cheers

Debug JavaScript file with variable names

I call my JavaScript files like this:
jsfilename.js?v=1234
And on each request I change the v parameter. Second request:
jsfilename.js?v=4567
Is that a way to debug on Chrome DevTools with this variable name?
Because now, every time I create a breakpoint and refresh the page, my breakpoint looses reference.

Use statement debugger in your JS code.
Don't forget to remove it after all ;-)

I would use console.log() to report back the variable name every time I need it. This should be able to show you the exact point where your script fails.

You can also disable cache while DevTool is open. Go to settings (click the 3 dots on the right and select settings) In this way you should refresh the page and not keep cache.
Errors are as mentioned in the other answer generally shown iin the console:-)

usually, you put ?v=xyz so that you can bypass browser cache [if the parameter is different, the browser gets the file from the server and not the cache].
this is used mostly whan you have to deal with CDN.
For debugging purposes, the Javascript debugger has an option to disable cache [open debug, go to settings; is the first checkbox in the "General" panel]
of course you can have problems in breakpoint persistence if the filename is diffeerent; so, as long as you're debugging, just disable cache, and, of course, don't place js file on CDN unless they're in their stable release;

Scrape sub elements in tables which cannot found in html but only in Chrome>F12>Element

I have tried to scrape scoring/event time and also player name http://en.gooooal.com/soccer/analysis/8401/events_840182.html.However cannot work.
require(RCurl);
require(XML);
lnk = "http://en.gooooal.com/soccer/analysis/8401/events_840182.html";
doc = htmlTreeParse(lnk,useInternalNodes=TRUE);
x = unlist(xpathApply(doc, "//table/tr/td"));
normal html page doesn't show the details of the table contents.
the nodes only can get from
>>> open Chrome >>> click F12 >>> click Element
Can someone help? Thanks a lot.

If you reload the page while Chrome developer tools are active, you can see that real data is fetched via XHR from http://en.gooooal.com/soccer/analysis/8401/goal_840182.js?GmFEjC8MND. This URL contains event id 840182 which you can scrape from the page. The part after ? seems to be just a way to circumvent browser caching. 8401, again, seems to be just first digits of the id.
So, you can load the original page, construct the second URL, and get real data from there.
Anyway... In most cases it's a morally questionalble practice to scrape data from web sites. I hope you know what you're doing :)

It sounds as if the content was inserted asynchronously using javascript, so using Curl won't help you there.
You'll need a headless browser which can actually parse and execute javascript (If you know ruby you could start looking for the cucumber-selenium-chromedriver combo), or maybe just use your browser with greasemonkey/tampermonkey to actually mimic a real user browsing the score scraping.

The contents are probably generated (by Javascript, like from an ajax call) after loading the (HTML) page. You can check that by loading the page in Chrome after disabling Javascript.
I don't think you can instruct RCurl to execute Javascript...

Javascript in asp.net MVC... Beginner issue

I created an Asp.Net MVC Internet Aplication and in my Index view of the Home Controller I have this
This is the first line, before the script results.
<script type="text/javascript" src="~/Script/Teste.js"></script>
<br />
This line comes after the script.
In my Teste.js I have this:
document.write("Yes! I am now a JavaScript coder!");
But nothing happens. If I change the src attribute and put some random name src="aaaa", despite the fact "aaaa" doesnt exist, I get no error in runtime.

EDIT
Also, check your path again. The default MVC templates in VS create a folder called Scripts, not Script. ("~/Scripts/teste.js")
Per the comment below, this was not the root cause of the issue, but in other cases can easily bite new JavaScript developers.
Most likely, your document.write function is firing before the document is ready, leading to the appearance that nothing is happening. Try the following in your Teste.js file
window.onload = function ()
{
document.write("Yes! I am now a JavaScript coder!");
//or even better as a test
alert("This alert was called");
}
Check the source of your page as well, it could be the document is being written to, you just can't see it due to markup/page styling.
As for you second issue, there will be no 'Runtime Exception' thrown if you reference a non-existent file. If you are using tools like Firebug or Chrome's developer tools, you should see a request to http://siteDomain/Scripts/aaaa.js with a response of 404, not found.

You generally should avoid using document.write() unless you absolutely have to use it for some reason... I don't think I've ever come across such a situation, and write a lot of Javascript.
Try this:
1) Put this in your HTML:
<script src="/scripts/teste.js"></script>
2) Put this in your JS:
alert('Yes! I am now a JavaScript coder!');
3) Open Chrome since it makes it easy to look for external resources loading and open the Network tab in Developer Tools (click the menu button at top-right, Tools > Developer Tools, Network tab).
4) Run your project and copy/paste the URL in the browser that comes up into this Chrome window, and hit enter.
When your page loads one of 2 things will happen:
A) You'll get the alert box you wanted or
B) You'll find out why it isn't loading because the Network tab will show the browser attempting to fetch teste.js and failing in some fashion, for example a 404, which would indicate you've got a typo in the path, or the script isn't where you thought it was, etc.

Put the following line at the very end of your document. There should not be anything after. Then try to load the page.
<script type="text/javascript" src="~/Script/Teste.js"></script>
Also, try pressing F12 once the page loads to see the source. Check if you script is there.

In MVC, the tilde is used to refer to the root URL of your application. However, it cannot normally parse this information. If you write:
<script src="~/Script/Teste.js"></script>
The lookup will fail, because the ~ means nothing special in HTML. If you're using Razor as your view engine (not ASPX), you need to wrap that call in Url.Content like so:
<script src="#Url.Content(~/Script/Teste.js)"></script>
Doing this will ensure a valid URL is provided to the browser.
With that in mind, you need to check that you have the file name and folder name both correct. You also need to ensure that the file is being deployed with your application. You can do this my opening the properties panel while the file is selected in the Solution Explorer and pressing F4.

javascript failing with permission denied error message

I have a classic ASP web page that used to work... but the network guys have made a lot of changes including moving the app to winodws 2008 server running iis 7.5. We also upgraded to IE 9.
I'm getting a Permission denied error message when I try to click on the following link:
<a href=javascript:window.parent.ElementContent('SearchCriteria','OBJECT=321402.EV806','cmboSearchType','D',false)>
But other links like the following one work just fine:
<a href="javascript:ElementContent('SearchCriteria','OBJECT=321402.EV806', 'cmboSearchType','D',false)">
The difference is that the link that is failing is in an iframe. I noticed on other posts, it makes a difference whether or not the iframe content is coming from another domain.
In my case, it's not. But I am getting data from another server by doing the following...
set objhttp = Server.CreateObject("winhttp.winhttprequest.5.1")
objhttp.open "get", strURL
objhttp.send
and then i change the actual html that i get back ... add some hyperlinks etc. Then i save it to a file on my local server. (saved as *.html files)
Then when my page is loading, i look for the specific html file and load it into the iframe.
I know some group policy options in IE have changed... and i'm looking into those changes. but the fact that one javascript link works makes me wonder whether the problem lies somewhere else...???
any suggestions would be appreciated.
thanks.

You could try with Msxml2.ServerXMLHTTP instead of WinHttp.WinHttpRequest.
See differences between Msxml2.ServerXMLHTTP and WinHttp.WinHttpRequest? for the difference between Msxml2.ServerXMLHTTP.
On this exellent site about ASP you get plenty of codesamples on how to use Msxml2.ServerXMLHTTP which is the most recent of the two:
http://classicasp.aspfaq.com/general/how-do-i-read-the-contents-of-a-remote-web-page.html
About the IE9 issue: connect a pc with an older IE or another browser to test if the browser that is the culprit. Also in IE9 (or better in Firefox/Firebug) use the development tools (F12) and watch the console for errors while the contents of the iFrame load.
Your method to get dynamic pages is not efficient i'm afraid, ASP itself can do that and you could use eg a div instead of an iframe and replace the contents with what you get from the request. I will need to see more code to give better advice.