How to catch javascript exceptions/errors? (To log them on server) - javascript

Duplicate:
Automatic feedback on JavaScript error
Logging JavaScript-Errors on Server
How would I go about logging errors in javascript? I can't wrap every line of javascript in try catch block.
I talking about the errors that for example in IE, would show an Error On page message and have the line and char the caused the error. If I can just figure out how to catch this error on the client side, I can just log the error on the server using an ajax call.

I use this function in all my projects:
window.onerror = function(m,u,l){
jQuery.post("ajax/js_error_log.php",
{ msg: m,
url: u,
line: l,
window: window.location.href });
return true};
Make sure it is the very first javascript the browser receives or at least precedes any potentially error-causing code. Requires jQuery of course, but you could code ajax functions in pure javascript if you wanted to.
Please note: this will not help you if you have a syntax error. All javascript instantly dies if there is a syntax error.

Related

Codeigniter 4 enviroment make JSON.parse fail

I'm new in codeigniter 4
I just started a new project in Codeigniter 4, and i got an error using JSON.parse,
Unexpected token < in JSON at position 30
I get two different results from using different enviroments:
Default// did not make any change to codeigniter config
-The code run totaly fine, though for a second i manage to see a bug in console
-The bad thing, in this enviroment most of debugging tools are deactivated something that i would like to have while working.
SetEnv CI_ENVIRONMENT production // which makes the debugging tools from CI4 appear, this line is in .htacess
-The code stops at JSON.parse and get the error described before in console
So here it is how my code is estructured:
//controller
echo json_encode(array('status' => 0,'message'=>'Access denied'));
//response rgets data from callback from a controller
console.log(response);//{status:0,message:'Access denied'}
data=JSON.parse(response); //error
//Other fixes i already tried
data=JSON.parse(JSON.stringify(response)); //Works fine, but returns a string, need an object
data=JSON.parse(JSON.parse(JSON.stringify(response))); //error
data=JSON.parse("{status:0,message:'Access denied'} "); //Even trying to use directly a JSON format throws error
data=JSON.parse({status:0,message:'Access denied'}) //error, without the comas
data=JSON.parse([{status:0,message:'Access denied'}]) //error
The debbuging tools seem to stop the loading when they find a bug, but i have not managed to find what i am doing wrong. Hope you can help me with this and thanks in advance.
EDIT
I´m using webix libraries for request, but they return string format.
I tried manually what you suggested,but the result was the same. It works if use CI4 in production env, but fails at development mode.
//Solutions tried
response = JSON.parse({"status":0,"message":"Access denied"});//error
response = JSON.parse("{'status':0,'message':'Access denied'}");//error
echo json_encode(array('status' => 0,'message'=>'Access denied'));
//the response should be like this
{"status":0,"message":"Access denied"}
and then use like this
data=JSON.parse(response);
and kindly check your datatype during the post and it should be a json

Node Js printing before execution

I am using node Js for automation and its printing all the console.log statements in one go, even before the browser opens up. Basically i have a print statement(console.log) after each line of code to make sure that my code has been executed, however this node.js prints all the print statement in one go.... even before the browser fires up... and then throws exception- element not found. How can i make sure that only after the code line has been executed, the next line executes ?? - below line of code, i am trying to execute...
Secondly, I am not able to make the script wait explicitly - in java there is a simple method Thread.sleep(5000) ...
how does it work in Javascript?
var un =driver.findElement(By.xpath("//input[#id='userName']")).sendKeys('CIT.XXXX');
console.log("login text entered");
var pwd =driver.findElement(By.xpath("//input[#id='password']")).sendKeys('ABCD123!');
console.log('Password keys Sent');
var Login =driver.findElement(By.xpath("//button[#id='smLogin']")).click();
console.log('Login Clicked');
You can use the library for synchronous processing in javascript.
Reference: https://github.com/caolan/async

XSS Payload not working

I am learning Website Pen-testing and trying to find XSS vulnerability.I use Firefox Browser.
Here is the site's code for search bar:
My payload is :
a" onmouseover="ALeRT(X)" size="50
which makes the code:
.
However the Payload doesn't get executed as it should. What could be the possible reason?
Since X is not defined, and it is not a variable, the alert function will not do anything and may error. Use alert(1) instead.

undefined result javascript

I have a simple javascript code, that validate when you write a order number and generates tags with javascript(with bootstrap-tagsinput js):
var order = $('#order_number').val();
if ($.inArray(order, $('#input_order_tags').val()) >= 0) {
$('#input_order_tags').tagsinput('add', order);
return;
}
var params = {
email: email,
order_code: order
}
AjaxServices.validateOrderNumberByEmail(params, function(error, result) {
if (error)
alert(error);
else
$('#input_order_tags').tagsinput('add', result.order);
});
This works fine but, every time trigger the error message when send a order number:
Console chrome debug:
How I can avoid the error of alert?
This is not a javascript issue. Server-side in you application you use order_code in one of the calls which returns the error message you see in the ajax call. Debug the offending call server-side, see which call returns that error and adjust your code so it works properly.
There might be two possibilities
client side issue ( javascript error) if so, its because the field order_number is disabled field.
as mentioned in this link
undefined index on javascript dynamic variables when passing to php form
If so, remove that disabled and use read-only and check if it works, without any error.
Server side issue( ajax call) if so, server side code which performs on call of that ajax call is causing that issue.

Uncaught SyntaxError: Unexpected token :

I am running an AJAX call in my MooTools script, this works fine in Firefox but in Chrome I am getting a Uncaught SyntaxError: Unexpected token : error, I cannot determine why. Commenting out code to determine where the bad code is yields nothing, I am thinking it may be a problem with the JSON being returned. Checking in the console I see the JSON returned is this:
{"votes":47,"totalvotes":90}
I don't see any problems with it, why would this error occur?
vote.each(function(e){
e.set('send', {
onRequest : function(){
spinner.show();
},
onComplete : function(){
spinner.hide();
},
onSuccess : function(resp){
var j = JSON.decode(resp);
if (!j) return false;
var restaurant = e.getParent('.restaurant');
restaurant.getElements('.votes')[0].set('html', j.votes + " vote(s)");
$$('#restaurants .restaurant').pop().set('html', "Total Votes: " + j.totalvotes);
buildRestaurantGraphs();
}
});
e.addEvent('submit', function(e){
e.stop();
this.send();
});
});
Seeing red errors
Uncaught SyntaxError: Unexpected token <
in your Chrome developer's console tab is an indication of HTML in the response body.
What you're actually seeing is your browser's reaction to the unexpected top line <!DOCTYPE html> from the server.
Just an FYI for people who might have the same problem -- I just had to make my server send back the JSON as application/json and the default jQuery handler worked fine.
This has just happened to me, and the reason was none of the reasons above. I was using the jQuery command getJSON and adding callback=? to use JSONP (as I needed to go cross-domain), and returning the JSON code {"foo":"bar"} and getting the error.
This is because I should have included the callback data, something like jQuery17209314005577471107_1335958194322({"foo":"bar"})
Here is the PHP code I used to achieve this, which degrades if JSON (without a callback) is used:
$ret['foo'] = "bar";
finish();
function finish() {
header("content-type:application/json");
if ($_GET['callback']) {
print $_GET['callback']."(";
}
print json_encode($GLOBALS['ret']);
if ($_GET['callback']) {
print ")";
}
exit;
}
Hopefully that will help someone in the future.
I have just solved the problem. There was something causing problems with a standard Request call, so this is the code I used instead:
vote.each(function(element){
element.addEvent('submit', function(e){
e.stop();
new Request.JSON({
url : e.target.action,
onRequest : function(){
spinner.show();
},
onComplete : function(){
spinner.hide();
},
onSuccess : function(resp){
var j = resp;
if (!j) return false;
var restaurant = element.getParent('.restaurant');
restaurant.getElements('.votes')[0].set('html', j.votes + " vote(s)");
$$('#restaurants .restaurant').pop().set('html', "Total Votes: " + j.totalvotes);
buildRestaurantGraphs();
}
}).send(this);
});
});
If anyone knows why the standard Request object was giving me problems I would love to know.
I thought I'd add my issue and resolution to the list.
I was getting: Uncaught SyntaxError: Unexpected token < and the error was pointing to this line in my ajax success statement:
var total = $.parseJSON(response);
I later found that in addition to the json results, there was HTML being sent with the response because I had an error in my PHP. When you get an error in PHP you can set it to warn you with huge orange tables and those tables were what was throwing off the JSON.
I found that out by just doing a console.log(response) in order to see what was actually being sent. If it's an issue with the JSON data, just try to see if you can do a console.log or some other statement that will allow you to see what is sent and what is received.
When you request your JSON file, server returns JavaScript Content-Type header (text/javascript) instead of JSON (application/json).
According to MooTools docs:
Responses with javascript content-type will be evaluated automatically.
In result MooTools tries to evaluate your JSON as JavaScript, and when you try to evaluate such JSON:
{"votes":47,"totalvotes":90}
as JavaScript, parser treats { and } as a block scope instead of object notation. It is the same as evaluating following "code":
"votes":47,"totalvotes":90
As you can see, : is totally unexpected there.
The solution is to set correct Content-Type header for the JSON file. If you save it with .json extension, your server should do it by itself.
It sounds like your response is being evaluated somehow. This gives the same error in Chrome:
var resp = '{"votes":47,"totalvotes":90}';
eval(resp);
This is due to the braces '{...}' being interpreted by javascript as a code block and not an object literal as one might expect.
I would look at the JSON.decode() function and see if there is an eval in there.
Similar issue here:
Eval() = Unexpected token : error
This happened to me today as well. I was using EF and returning an Entity in response to an AJAX call. The virtual properties on my entity was causing a cyclical dependency error that was not being detected on the server. By adding the [ScriptIgnore] attribute on the virtual properties, the problem was fixed.
Instead of using the ScriptIgnore attribute, it would probably be better to just return a DTO.
This happened to because I have a rule setup in my express server to route any 404 back to /# plus whatever the original request was. Allowing the angular router/js to handle the request. If there's no js route to handle that path, a request to /#/whatever is made to the server, which is just a request for /, the entire webpage.
So for example if I wanted to make a request for /correct/somejsfile.js but I miss typed it to /wrong/somejsfile.js the request is made to the server. That location/file does not exist, so the server responds with a 302 location: /#/wrong/somejsfile.js. The browser happily follows the redirect and the entire webpage is returned. The browser parses the page as js and you get
Uncaught SyntaxError: Unexpected token <
So to help find the offending path/request look for 302 requests.
Hope that helps someone.
If nothing makes sense, this error can also be caused by PHP Error that is embedded inside html/javascript, such as the one below
<br />
<b>Deprecated</b>: mysql_connect(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead in <b>C:\Projects\rwp\demo\en\super\ge.php</b> on line <b>54</b><br />
var zNodes =[{ id:1, pId:0, name:"ACE", url: "/ace1.php", target:"_self", open:true}
Not the <br /> etc in the code that are inserted into html by PHP is causing the error. To fix this kind of error (suppress warning), used this code in the start
error_reporting(E_ERROR | E_PARSE);
To view, right click on page, "view source" and then examine complete html to spot this error.
"Uncaught SyntaxError: Unexpected token" error appearance when your data return wrong json format, in some case, you don't know you got wrong json format.
please check it with alert(); function
onSuccess : function(resp){
alert(resp);
}
your message received should be: {"firstName":"John", "lastName":"Doe"}
and then you can use code below
onSuccess : function(resp){
var j = JSON.decode(resp); // but in my case i'm using: JSON.parse(resp);
}
with out error "Uncaught SyntaxError: Unexpected token"
but if you get wrong json format
ex:
...{"firstName":"John", "lastName":"Doe"}
or
Undefined variable: errCapt in .... on line<b>65</b><br/>{"firstName":"John", "lastName":"Doe"}
so that you got wrong json format, please fix it before you JSON.decode or JSON.parse
I had the same problem and it turned out that the Json returned from the server
wasn't valid Json-P. If you don't use the call as a crossdomain call use regular Json.
My mistake was forgetting single/double quotation around url in javascript:
so wrong code was:
window.location = https://google.com;
and correct code:
window.location = "https://google.com";
In my case putting / at the beginning of the src of scripts or href of stylesheets solved the issue.
I got this error because I was missing the type attribute in script tag.
Initially I was using but when I added the type attribute inside the script tag then my issue is resolved
I got a "SyntaxError: Unexpected token I" when I used jQuery.getJSON() to try to de-serialize a floating point value of Infinity, encoded as INF, which is illegal in JSON.
In my case i ran into the same error, while running spring mvc application due to wrong mapping in my mvc controller
#RequestMapping(name="/private/updatestatus")
i changed the above mapping to
#RequestMapping("/private/updatestatus")
or
#RequestMapping(value="/private/updatestatus",method = RequestMethod.GET)
For me the light bulb went on when I viewed the source to the page inside the Chrome browser. I had an extra bracket in an if statement. You'll immediately see the red circle with a cross in it on the failing line. It's a rather unhelpful error message, because the the Uncaught Syntax Error: Unexpected token makes no reference to a line number when it first appears in the console of Chrome.
I did Wrong in this
`var fs = require('fs');
var fs.writeFileSync(file, configJSON);`
Already I intialized the fs variable.But again i put var in the second line.This one also gives that kind of error...
For those experiencing this in AngularJs 1.4.6 or similar, my problem was with angular not finding my template because the file at the templateUrl (path) I provided couldn't be found. I just had to provide a reachable path and the problem went away.
In my case it was a mistaken url (not existing), so maybe your 'send' in second line should be other...
This error might also mean a missing colon or : in your code.
Facing JS issues repetitively I am working on a Ckeditor apply on my xblock package. please suggest to me if anyone helping me out. Using OpenEdx, Javascript, xblock
xblock.js:158 SyntaxError: Unexpected token '=>'
at eval (<anonymous>)
at Function.globalEval (jquery.js:343)
at domManip (jquery.js:5291)
at jQuery.fn.init.append (jquery.js:5431)
at child.loadResource (xblock.js:236)
at applyResource (xblock.js:199)
at Object.<anonymous> (xblock.js:202)
at fire (jquery.js:3187)
at Object.add [as done] (jquery.js:3246)
at applyResource (xblock.js:201) "SyntaxError: Unexpected token '=>'\n at eval (<anonymous>)\n at Function.globalEval (http://localhost:18010/static/studio/common/js/vendor/jquery.js:343:5)\n at domManip (http://localhost:18010/static/studio/common/js/vendor/jquery.js:5291:15)\n at jQuery.fn.init.append (http://localhost:18010/static/studio/common/js/vendor/jquery.js:5431:10)\n at child.loadResource (http://localhost:18010/static/studio/bundles/commons.js:5091:27)\n at applyResource (http://localhost:18010/static/studio/bundles/commons.js:5054:36)\n at Object.<anonymous> (http://localhost:18010/static/studio/bundles/commons.js:5057:25)\n at fire (http://localhost:18010/static/studio/common/js/vendor/jquery.js:3187:31)\n at Object.add [as done] (http://localhost:18010/static/studio/common/js/vendor/jquery.js:3246:7)\n at applyResource (http://localhost:18010/static/studio/bundles/commons.js:5056:29)"
Late to the party but my solution was to specify the dataType as json. Alternatively make sure you do not set jsonp: true.
Try this to ignore this issue:
Cypress.on('uncaught:exception', (err, runnable) => {
return false;
});
Uncaught SyntaxError: Unexpected token }
Chrome gaved me the error for this sample code:
<div class="file-square" onclick="window.location = " ?dir=zzz">
<div class="square-icon"></div>
<div class="square-text">zzz</div>
</div>
and solved it fixing the onclick to be like
... onclick="window.location = '?dir=zzz'" ...
But the error has nothing to do with the problem..

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