You can use the [`debugger`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/debugger) statement:

    // your JS code
    ...
    // break here
    debugger;

It works in all major browsers.

I&#39;m using jQuery&#39;s autocomplete in a relatively simple way:

    $(document).ready(function() {
      var data = [ {text: &quot;Choice 1&quot;}, 
                   {text: &quot;Choice 2&quot;}, 
                   {text: &quot;Choice 3&quot;} ]
     
    $(&quot;#example&quot;).autocomplete(data, {
      matchContains: true,
      minChars: 0,
      formatItem: function(item) 
        { return item.text; }
        }
      );
      });

How do I add an onclick event (like a button or a link) that will display all the available choices for the autocomplete? Basically I&#39;m looking to make a hybrid of an autocomplete and a select/dropdown element.

Thanks!

jQuery autoComplete view all on click?

I have a form that users fill out, and on the form there are multiple identical fields, like &quot;project name&quot;, &quot;project date&quot;, &quot;catagory&quot;, etc. Based on how many forms a user is submitting, my goal is to:

 1. loop over the number of forms
 2. create individual SQL insert statements


However, PHP throws me a NOTICE that I don&#39;t seem to understand:

**Notice:**
&gt; Notice: Uninitialized string offset: 1 ...dataPasser.php on line 90


**PHP**

	$myQuery = array();
		
	if ($varsCount != 0)
	{
	  for ($i=0; $i &lt;= $varsCount; $i++)
	  {
		$var = &quot;insert into projectData values (&#39;&quot; . $catagory[$i] . &quot;&#39;, &#39;&quot; .  $task[$i] . &quot;&#39;, &#39;&quot; . $fullText[$i] . &quot;&#39;, &#39;&quot; . $dueDate[$i] . &quot;&#39;, null, &#39;&quot; . $empId[$i] .&quot;&#39;)&quot;;
		array_push($myQuery, $var);		
	  }
	}

There are references to this issue I am having, but they are not exact and I am having trouble deducing where the actual problem stems from. I would greatly appreciate any help in understanding what is causing the array to not initialize properly.

What causes: &quot;Notice: Uninitialized string offset&quot; to appear?

I am currently debugging complex JavaScript code with Firebug. I am looking for a way to stop the JavaScript execution as if it was a breakpoint programmatically.

Example:

    instructions ...
    degugger.breakpoint(); // the execution stops here as if a breakpoint was
                           // manually set
    other instructions ...



Programmatically stop JavaScript execution in Firebug

I am currently debugging complex JavaScript code with Firebug. I am looking for a way to stop the JavaScript execution as if it was a breakpoint programmatically.
Example:
<pre><code class="hljs language-scss">instructions ...
degugger.breakpoint(); // the execution stops here as if a breakpoint was
 // manually set
other instructions ...
</code></pre>

I am dynamically creating a hyperlink in the c# code behind file of ASP.NET. I need to call a JavaScript function on client click. how do i accomplish this?

call javascript function on hyperlink click

What is the recommended way to zerofill a value in JavaScript? I imagine I could build a custom function to pad zeros on to a typecasted value, but I&#39;m wondering if there is a more direct way to do this?

**Note:** By &quot;zerofilled&quot; I mean it in the database sense of the word (where a 6-digit zerofilled representation of the number 5 would be &quot;000005&quot;).

How can I pad a value with leading zeros?

It seems that I am unable to change most request headers from JavaScript when making an AJAX call using XMLHttpRequest.  Note that when `request.setRequestHeader` has to be called after `request.open()` in Gecko browsers (see http://ajaxpatterns.org/Talk:XMLHttpRequest_Call).  When I set the *Referer*, it doesn&#39;t get set (I looked at the request headers sent using Firebug and Tamper Data).  When I set *User-Agent*, it messed up the AJAX call completely. Setting *Accept* and *Content-Type* does work, however. Are we prevented from setting *Referer* and *User-Agent* in Firefox 3?

&lt;!-- language: lang-js --&gt;

    var request = new XMLHttpRequest();
    var path=&quot;http://www.yahoo.com&quot;;
    request.onreadystatechange=state_change;
    
    request.open(&quot;GET&quot;, path, true);
    request.setRequestHeader(&quot;Referer&quot;, &quot;http://www.google.com&quot;);
    //request.setRequestHeader(&quot;User-Agent&quot;, &quot;Mozilla/5.0&quot;);
    request.setRequestHeader(&quot;Accept&quot;,&quot;text/plain&quot;);
    request.setRequestHeader(&quot;Content-Type&quot;,&quot;text/plain&quot;);
    
    request.send(null);
    	function state_change()
    {
    if (request.readyState==4)
      {// 4 = &quot;loaded&quot;
      if (request.status==200)
        {// 200 = OK
        // ...our code here...
    	alert(&#39;ok&#39;);
        }
      else
        {
        alert(&quot;Problem retrieving XML data&quot;);
        }
      }
    }

Set a request header in JavaScript

I would suspect this to work at first:

    if ($(&#39;#element&#39;) == $(&#39;#element&#39;)) alert(&#39;hello&#39;);

But it does not.  How does one test if elements are the same?

Test if two elements are the same

I&#39;m using the jQuery plugin [Validation][1] to validate a form. I have a select list looking like this:

    &lt;select id=&quot;select&quot;&gt;
    &lt;option value=&quot;&quot;&gt;Choose an option&lt;/option&gt;
    &lt;option value=&quot;option1&quot;&gt;Option1&lt;/option&gt;
    &lt;option value=&quot;option2&quot;&gt;Option2&lt;/option&gt;
    &lt;option value=&quot;option3&quot;&gt;Option3&lt;/option&gt;
    &lt;/select&gt;

Now, I want to make sure that the user selects anything but &quot;Choose an option&quot; (which is the default one). So that it won&#39;t validate if you choose the first option. How can this be done?


  [1]: http://plugins.jquery.com/project/validate

Validate select box

The question says it all. If you have a bug that multiple users report, but there is no record of the bug occurring in the log, nor can the bug be repeated, no matter how hard you try, how do you fix it? Or even can you?

I am sure this has happened to many of you out there. What did you do in this situation, and what was the final outcome?


----------


Edit:
I am more interested in what was done about an *unfindable* bug, not an unresolvable bug. Unresolvable bugs are such that you at least know that there is a problem and have a starting point, in most cases, for searching for it. In the case of an unfindable one, what do you do? Can you even do anything at all?

How do you fix a bug you can&#39;t replicate?

How do I disable assertions in Python?

That is, if an assertion fails, I don&#39;t want it to throw an `AssertionError`, but to keep going.

How do I do that?

Disable assertions in Python

I have one crash in my iPhone application that does throw an NSException. The crash reports are completely ambiguous in where the error is and what exactly is causing it. Is there a smart way for me to set a top level exception handler somewhere to see what is causing it? I can&#39;t replicate the problem myself, but a few of my beta users certainly can.

What&#39;s a smart way to handle a problem of this nature?

How do you implement global iPhone Exception Handling?

How can I step through JDK source code in IntelliJ IDEA 7 and see the debug info?  I can currently hit breakpoints and step through the code, but the debug info is not available.  This means I can&#39;t see the value of local variables.

I only want to step through the source code of one class, if that matters.  
For what it&#39;s worth, it&#39;s the `javax.swing.text.html.HTMLDocument` class and I do have a copy of the corresponding `.java` file.


Step through JDK source code in IntelliJ IDEA

I&#39;m just getting started using ADO.NET and DataSets and DataTables. One problem I&#39;m having is it seems pretty hard to tell what values are in the data table when trying to debug.

What are some of the easiest ways of quickly seeing what values have been saved in a DataTable? Is there someway to see the contents in Visual Studio while debugging or is the only option to write the data out to a file?

I&#39;ve created a little utility function that will write a DataTable out to a CSV file. Yet the the resulting CSV file created was cut off. About 3 lines from what should have been the last line in the middle of writing out a System.Guid the file just stops. I can&#39;t tell if this is an issue with my CSV conversion method, or the original population of the DataTable.

**Update**

Forget the last part I just forgot to flush my stream writer.



How to view a DataTable while debugging

    var list = [];
    $.getJSON(&quot;json.js&quot;, function(data) {
        $.each(data, function(i, item) {
            console.log(item.text);
            list.push(item.text);
        });
    });
    console.log(list.length);


`list.length` always returns 0.  I&#39;ve browsed the JSON in firebug and it&#39;s well formed and everything looks fine.  I just can&#39;t seem to add an item to the array what am I missing?


How do I add items to an array in jQuery?

Sometimes I need to inspect elements that are only showing up on a page if you put mouse over some area. The problem is that if you start moving mouse towards firebug console in order to see the changes, mouse-out event is triggered and all changes I am trying to inspect disappear. How to deal with such cases?

Basically I am looking for something that would either:

  - Switch to firebug console without moving a mouse (using keyboard shortcuts maybe? But I can&#39;t figure out how to use firebug with keyboard only)
  - Have an ability to &quot;freeze&quot; the page so your mouse movements don&#39;t trigger any events anymore.

Thanks.

Firebug: How to inspect elements changing with mouse movements?

I&#39;m looking for a tool that will give me the proper generated source including DOM changes made by AJAX requests for input into W3&#39;s validator. I&#39;ve tried the following methods:


 1. 
[Web Developer Toolbar][1] - Generates invalid source according to the doc-type (e.g. it removes the self closing portion of tags). Loses the doctype portion of the page.
 2. [Firebug][2] - Fixes potential flaws in the source (e.g. unclosed tags). Also loses doctype portion of tags and injects the console which itself is invalid HTML.
 3. IE Developer Toolbar - Generates invalid source according to the doc-type (e.g. it makes all tags uppercase, against XHTML spec).
 4. Highlight + View Selection Source - Frequently difficult to get the entire page, also excludes doc-type.

Is there any program or add-on out there that will give me the exact current version of the source, without fixing or changing it in some way? So far, Firebug seems the best, but I worry it may fix some of my mistakes.

**Solution**

It turns out there is no exact solution to what I wanted as Justin explained. The best solution seems to be to validate the source inside of Firebug&#39;s console, even though it will contain some errors caused by Firebug. I&#39;d also like to thank Forgotten Semicolon for explaining why &quot;View Generated Source&quot; doesn&#39;t match the actual source. If I could mark 2 best answers, I would.

  [1]: https://addons.mozilla.org/en-US/firefox/addon/60 &quot;Web Developer Toolbar&quot;
  [2]: https://addons.mozilla.org/en-US/firefox/addon/1843

Best Way to View Generated Source of Webpage?

I have an object I need to examine in IE8.
I tried the developer tools and `console.log`, their Firebug equivalent.
However, when I output the object to the log:

    console.log(&quot;Element: &quot;, element);
    console.log(element);

I only get the string

    LOG: Element: [object Object]

instead of a clickable, examinable dump.

Is it possible to dump an object to the Log and examine its members, like in Firebug?

I can&#39;t use a homemade dump() function because the element I want to examine is so huge the browser will crash on me. 



How do I dump JavaScript vars in IE8?

I have been working with web workers in HTML 5 and am looking for ways to debug them. Ideally something like the firebug or chrome debuggers.  Does anyone have any good solution to this. with no access to the console or DOM its kind of hard to debug iffy code

How to debug web workers

Is there a single command in gdb which can set breakpoints on all the functions in a given file ?
I know about rbreak regex which sets breakpoints in matching regular expression functions, but my file doesnt have fixed patterned functions. 

In another way, is there a command by which I can set a breakpoint on a filename. Which will mean, whenever control gets inside this file, it should break ?

I personally think this should not be much difficult to implement in gdb, but just wondering if somebody has already done this.

gdb, set breakpoint on all functions in a file

Is there any way to remove all the breakpoints in Xcode?

Xcode + remove all breakpoints

When I am at a breakpoint and if I want to ignore all the rest of breakpoints and move on, what shortcut should I use?

What is the shortcut to skip all break-points in VS?

A C# desktop application (on the Visual Studio Express/Community edition) worked, but then it didn&#39;t work 5 seconds later.

I tried the following:

* Ensure debug configuration, debug flag, and full debug information are set on all assemblies.
* Delete all bin and obj folders and all DLL files related to the project from my entire machine.
* Recreate projects causing the problem from scratch.
* Reboot.

I have two Windows Forms projects in the solution. One of them loads the debug information, one doesn&#39;t. They both refer to the assembly I&#39;m trying to get debug information on in exactly the same way in the project file. Any ideas?

----

I want to add here, mostly for myself when I come back to review this question, that symbols are not loaded until the assembly is loaded, and the assembly is not loaded until it is needed. If the breakpoint is in a library that is only used in one function in your main assembly, the symbols will not be loaded (and it will show the breakpoint as not being hit) until that function is called.



How do I remedy &quot;The breakpoint will not currently be hit. No symbols have been loaded for this document.&quot; warning?

I have a multithreaded app that is very stable on all my test machines and seems to be stable for almost every one of my users (based on no complaints of crashes).  The app crashes frequently for one user, though, who was kind enough to send crash reports.  All the crash reports (~10 consecutive reports) look essentially identical:

    Date/Time:       2010-04-06 11:44:56.106 -0700
    OS Version:      Mac OS X 10.6.3 (10D573)
    Report Version:  6
    
    Exception Type:  EXC_BREAKPOINT (SIGTRAP)
    Exception Codes: 0x0000000000000002, 0x0000000000000000
    Crashed Thread:  0  Dispatch queue: com.apple.main-thread
    
    Thread 0 Crashed:  Dispatch queue: com.apple.main-thread
    0   com.apple.CoreFoundation      	0x90ab98d4 __CFBasicHashRehash + 3348
    1   com.apple.CoreFoundation      	0x90adf610 CFBasicHashRemoveValue + 1264
    2   com.apple.CoreText            	0x94e0069c TCFMutableSet::Intersect(__CFSet const*) const + 126
    3   com.apple.CoreText            	0x94dfe465 TDescriptorSource::CopyMandatoryMatchableRequest(__CFDictionary const*, __CFSet const*) + 115
    4   com.apple.CoreText            	0x94dfdda6 TDescriptorSource::CopyDescriptorsForRequest(__CFDictionary const*, __CFSet const*, long (*)(void const*, void const*, void*), void*, unsigned long) const + 40
    5   com.apple.CoreText            	0x94e00377 TDescriptor::CreateMatchingDescriptors(__CFSet const*, unsigned long) const + 135
    6   com.apple.AppKit              	0x961f5952 __NSFontFactoryWithName + 904
    7   com.apple.AppKit              	0x961f54f0 +[NSFont fontWithName:size:] + 39

(....more text follows)

First, I spent a long time investigating [NSFont fontWithName:size:].  I figured that maybe the user&#39;s fonts were screwed up somehow, so that [NSFont fontWithName:size:] was requesting something non-existent and failing for that reason.  I added a bunch of code using [[NSFontManager sharedFontManager] availableFontNamesWithTraits:NSItalicFontMask] to check for font availability in advance.  Sadly, these changes didn&#39;t fix the problem.

I&#39;ve now noticed that I forgot to remove some debugging breakpoints, including _NSLockError, [NSException raise], and objc_exception_throw.  However, the app was definitely built using &quot;Release&quot; as the active build configuration.  I assume that using the &quot;Release&quot; configuration prevents setting of any breakpoints--but then again I am not sure exactly how breakpoints work or whether the program needs to be run from within gdb for breakpoints to have any effect.

My questions are: could my having left the breakpoints set be the cause of the crashes observed by the user?  If so, why would the breakpoints cause a problem only for this one user?  If not, has anybody else had similar problems with [NSFont fontWithName:size:]?

I will probably just try removing the breakpoints and sending back to the user, but I&#39;m not sure how much currency I have left with that user.  And I&#39;d like to understand more generally whether leaving the breakpoints set could possibly cause a problem (when the app is built using &quot;Release&quot; configuration).

Content Type	Original Author	Original Content on Stackoverflow
Question	Nikko	View Question on Stackoverflow
Solution 1 - Javascript	RaYell	View Answer on Stackoverflow

Programmatically stop JavaScript execution in Firebug

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

What causes: "Notice: Uninitialized string offset" to appear?

jQuery autoComplete view all on click?

Attributions