Claudiu Persoiu

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Archive for the ‘Internet Explorer’ tag

Internet Explorer, select tag and onload

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Another reason why I hate Internet Explorer.

All new browsers tend to cache form values. Nothing unusual up to here, a little annoying, but not unusual.

We have the following example:

<select id="select">
 <option value=a>a</option>
 <option value=b>b</option>
 <option value=c>c</option>

var checkSelected = function () {
 var element = document.getElementById('select');

// run after onload
window.onload = checkSelected;

// run before onload


Load the page, select the third value and then refresh. Because no form was submitted the first impression is that the result will always be “a”. It seems it’s not really like that:

  • FireFox: c c
  • Google Chrome: a a
  • Internet Explorer: a c

I can understand why FireFox choose to cache the values even when no form was submitted.

I can understand Google Chrome for not caching the page if the form was not submitted.

But Internet Explorer caches the values and them loads them only after the page was loaded? This is confusing to me! I mean you don’t have the option of not using onload? Not even if the form was not submitted?

This test was made on Internet Explorer 9 and compatibility view to versions 7 and 8.

Written by Claudiu Persoiu

9 October 2011 at 2:09 PM

Unknown runtime error – Internet Explorer with InnerHTML – another meaningful error

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I was working the other day on a new JavaScript game for the games section. Like the majority of the developers (like the statistics show) I’m using FireFox for developing. But as the game reached the testing faze it was time to see if it was working properly in Internet Explorer.

To test in Internet Explorer is a real pleasure, basically you see an error and then you hope that you’ll find the source.

Of course there was an error, one full of meaning as usual:

Unknown runtime error??? WTF??? If he does not know how should I?

The piece of code that was generating the error was:

canvas.innerHTML = '';

Where canvas was a variable which was storing an document.getElementById(‘canvas’), and the id canvas was from:

<table border="0" cellspacing="0" cellpadding="0">
<tbody id="canvas"></tbody>

Looks wrong? well is not because at that point I was testing other games which are using the same thing with no trouble, even in IE.

I’ve tried it in IE 6, of course with the same result.

It looks like this error appears on elements like table, tbody, p and others.

To finally fix the issue I used instead of a tbody, a div tag in which I’m adding the elements and the issue was gone.

What is interesting is that this issue does not always appear for a specific tag!

Thank you Microsoft for this meaningful error messages that are so full of logic!

Written by Claudiu Persoiu

6 June 2010 at 2:20 PM

Software adoption rate and web development

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How does the rate of adoption of new software products and/or version influences the software development for Web and client-server type products?
From the perspective of a web developer, we are restricted by the servers for which we develop and our client’s browsers. Compromise often go very far for the sake of meeting a more broader market.


Currently stable version of PHP is 5.3.0, but using this version in production would be a childish decision. The version has been out for a little while and the probability to find this version on the hosting servers is very slim.

Of course, a more appropriate version is 5.2.10.  And yet, if version 5 was released almost 5 years now, why a popular framework like CakePHP yet uses the advantages brought by this version? Because until recently an important part of shared hosting servers that have support for PHP, still had version 4.

How is this translated in production? If you don’t develop internal products, or on your own servers, or servers which you can control, you should be aware that your product should be compatible with older PHP versions, and the new features of the language should not be used in production.
Ridiculous and sad but true.
PHP 5.3 brings quite a lot of new features,  but until these features can be used in production few years will have to pass. And until they get in frameworks probably even more (ie namespaces are useful in frameworks).


Current stable version is 5.1.36. 5.x version, released in2005 brought many new features, some of them are: stored routines (functions and procedures), triggers, views, cursors, information schema, etc.

Stored routines is probably one of the biggest changes. They are probably most known from Oracle PL/SQL, although MySQL has implemented from the ANSI SQL 2003standard.

Because MySQL 5.0 was in beta for a long time, the rate of adoption is very low. Again, after almost 4 years since the version was released, and it is not yet sufficiently widespred.

Conclusion, simply put it is not recommended the use of the new features if you can not control the version on the server.

Browsers and JavaScrip

The browser problem affects both developers and designers.

Probably the oldest browser still used on a large enough scale is Internet Explorer 6. It was launched in 2001 and after 8 years it is still used by ~ 30% of users.

JavaScript in 2001 was still considered a scripting language infant, which was mostly used for visual effects.

After the “discovery” of AJAX in 2005 , JavaScript was reborn. JavaScript was not just a scripting language used for reduced visual effects, but was regarded as a technology of the future.

Browsers such as FireFox, Opera, Google Chrome or Safari have made progress to improve the speed of JavaScript execution. Even Internet Explorer 8 works better with JavaScript, but it is far from being as popular as version 6. And for the problem to be complete, Microsoft has a big issue with keeping the compatibility between their products.

The reason for this problem in adoption of new versions of Internet Explorer is the operating system. The most popular operating system is Microsoft Windows XP and it has pre-installed Internet Explorer 6. Given that Windows Vista had a fairly low adoption rate because of the initial bugs, drivers issues, resource consumption, and other problems, meant that Windows XP was still very popular. Of course not everyone using Windows XP use IE 6, many have updated or simply use another browser. But still many of them are using the browser that is default.

Speaking of this, Windows 7 will be distributed in Europe without IE installed. I’m very curious how will this influence the browsers market.

Lately “smart phones” and PDA devices have become increasingly popular. A lot of people use them to navigate on the Internet. So after the issues related to browsers on PCs, now there is a hole new set of issues on mobile device browsers.

For instance, my phone came with two browsers: Internet Explorer and Opera. Internet Explorer Mobile is terrible, so I’m using Opera which does a good job.

The problem is that many PDA / smart phone devices with Windows Mobile OS only have Internet Explorer in standard, and the previous problem returns.
When it comes to the famous Apple iPhone, Safari browser is used (and I believe that you can’t install another browser, but I’m not sure if that is true any longer).
So when you create an interface or a JavaScript application, you must take into account several aspects such as:

  • device(eg PC, PDA, smart phone etc.)
  • operating system (eg Windows, Linux, Mac, Symbian etc.)
  • browsers and there versions (eg Internet Explorer 6,7,8; FireFox, Safari, Opera etc.)
  • HTML 5 is almost here, but when it comes to browsers, I wonder when will we be able to use it on a large scale, given that the market is currently dominated by IE 6 and 7.

    I give it about 5 years…

    Written by Claudiu Persoiu

    15 July 2009 at 9:55 PM

    Plug-inuri Firefox utile pentru developeri

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    Si acesta este unul dintre motivele pentru care eu prefer FireFox!

    Ca tot scriam de unelte utile si nepromovate in postul trecut, acum m-am gandit sa listez cateva plug-in-uri interesante pentru browserul meu favorit, FireFox!

    Si acestea sunt cateva plugin-uri care mi se par utile cand vine vorba de development si nu numai:

    YSlow – dezvoltat de Yahoo! pentru a urmarii cateva reguli de baza pentru viteza de incarcare a paginii

    Web Development toolbar – adauga un toolbar cu diverse instrumente foarte utile pentru development

    Firebug – unealta arhicunoscuta pentru debuging live de DOM si CSS

    Live HTTP Headers – pentru a se vedea headerele care transmit in tranzactii si chiar genera raspunsuri

    IE Tab – afisaza pagina in motorul de Internet Explorer… fara sa-l deschida, foarte util pentru teste de compatibilitate fara a fi nevoie sa se deschida o noua fereastra, iar schimbarea se face cu un singur click

    ColorZilla – una dintre facilitatiile foarte interesante este care are un picker de culori care se poate folosi direct in browser, asta pe langa multe alte unelte

    FireShot – pentru screenshot-uri de pagina direct in browser, una din facilitatile utile este ca se pot face screenshot-uri la intreaga pagina (inclusiv zonele care nu se vad)

    MeasureIt – traseaza linii pentru a masura elemente din pagina

    Venkman – debugger de JavaScript (despre care am mai scris)

    FireFTP – client ftp pentru FireFox, simplu si util

    Console2 – un inlocuitor mai avansat pentru Error console

    Regular Expression Tester – cum spune si numele, unealta pentru expresii regulate

    Nagios Checker – pentru monitorizarea serverelor

    Live PageRank – pentru a vedea PR-ul paginii curente

    Evident lista este scurta si nu sunt decat cateva plug-in-uri care le prefer eu. Lista completa este gigantica si cuprinde cam tot ce ai visat sa aiba un browserul si chiar mai mult.

    Written by Claudiu Persoiu

    21 April 2009 at 11:16 PM

    JavaScript debugging cu Venkman

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    Din ciclul unelte utile dar nepromovate, in aceasta seara avem o mica unelta numita Venkman. Unealta este realizata ca extensie pentru FireFox si se foloseste pentru debugging a codului JavaScript.

    Nu stiu daca mi se pare mie sau chiar sunt foarte putine instrumente pentru asa ceva? Google Chrome are niste unelte foarte interesante pentru urmarirea proceselor JavaScript, iar probabil la polul opus se afla Internet Explorer cu niste mesaje deosebit de generice (si suficient de inutile) cu privire la erorile gasite.

    Dar de multe ori nu sunt erori de cod ci erori de logica.

    Dar sa revenim la Venkman, acesta ofera posiblitatea de a urmarii executia pas cu pas, de a opri un script sau de a continua. Imi aduce aminte de uneltele din Visual Studio pentru C++, evident nu este la nivelul acela dar este un mare pas inainte pentru JavaScript.

    In ultimele luni am incercat sa fac mici joculete in JavaScript, iar o astfel de unealta mi se pare foarte utila pentru a urmarii executia pas cu pas.

    Oricum mi se pare ca JavaScript a devenit doar de putin timp apreciat la adevaratul potential, iar aceste unelte aduc limbajul la nivelul la care merita.

    Written by Claudiu Persoiu

    18 April 2009 at 12:05 AM

    Un browser… multe frustrari…

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    A fost o data ca niciodata Internet Explorer 6. Sunt sigur ca toata lumea a avut placerea sa-l cunoasca, sa-l foloseasca etc.

    Cand eram la inceputuri foloseam Internet Explorer ca sa testez ce faceam, pana sa aflu ca FireFox este mult superior pentru…. eh, e mai bun pentru orice.

    Cand a aparut Vista ma gandeam ca unele lucruri o sa se schimbe, dar… nu a fost asa, iar Vista se pare ca a fost un dezastru mai mare decat era anticipat. O data cu asta XP a mai primit niste ani de gratie si o data cu el… Internet Explorer 6.

    Sa nu ma intelegeti gresit Internet Explorer 6 chiar mi se pare un browser reusit, a fost chiar foarte bun la vremea lui, dar vremea lui a cam trecut! Cum poate compara cineva FireFox 3 cu el? Ca sa nu ne gandim ca IE 8 e pe drum, iar la noi IE 6 inca este cel mai popular.

    Gata! Prea multi developeri si designeri frustati si chinuiti! Internet Explorer 6 trebuie sa dispara!

    Written by Claudiu Persoiu

    11 April 2009 at 3:40 PM

    Posted in Browsers

    Tagged with ,

    Argumentele id si name in Internet Explorer si FireFox

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    Ca tot postam zilele trecute legat de incompatibilitati cu adevarat enervante, zilele trecute am descoperit un bug care l-am plantat cu succes de mai bine de un an jumatate.

    Aveam niste campuri, respectiv:

    <input id="cos1" name="cos20" type="text" />
    <input id="cos2" name="cos19" type="text" />
    <input id="cos3" name="cos18" type="text" />
    <input id="cos10" name="cos11" type="text" />
    <input id="cos11" name="cos10" type="text" />

    Ideea era ca atunci cand trebuie sa verific din JavaScript sa o fac folosind un for() iar din PHP folosind numele.

    Codul JavaScript arata cam asa:

    for(var i=1; i<=coshmax; i++)
         element = document.getElementById("cos"+i).value;
         if(element>0 && !isNaN(element))

    Pana aici totul bine, am testat aplicatia de nenumarat ori si nu a fost nici o problema.

    Pana acum cateva zile cand am primit o reclamatie ca exista o problema pe la ultimele optiuni, respectiv asta se traduce prin ultimele variabile. Am inceput sa testez in Internet Explorer pentru ca acesta era deschis, apoi am testat si in FireFox ca sa urmaresc codul JavaScript si surpriza… in FireFox mergea fara probleme.

    Am pierdut aproape jumatate de ora holbandu-ma si punand alert()-uri ca sa inteleg ce se petrece, apoi am realizat: Internet Explorer nu face mare diferenta intre id si name.

    Problema era ca atunci cand apelam id-ul cos10 primeam valoarea de la id=”cos10″, cand testam cos11 primeam valoarea de la name=”cos11″. Rezultatul: nu mai testam ultima variabila nicioada.

    Evident solutia a fost simpla, am redenumit id-urile ca sa nu mai existe artibute name si id cu aceeasi valoare.

    Cazul acesta nu a fost foarte “trist” pentru ca am rasit bug-ul si am putut sa trec mai departe la ce faceam, dar daca eram la final de program dupa o zi agitata cred ca rezultatul era cu totul altul.

    Problema este cu atat mai ciudata cu cat daca uiti sa redenumesti un element poti sa te trezesti cu un bug de toata frumusetea, respectiv daca in loc sa dai la un element name ii dai id, o sa mearga in Internet Explorer si… cam atat, de ex:

    <input type="text" id="variabila" />

    in Internet Explorer va fi trimis foarte frumos ca orice alta variabila, iar in alte browsere cum ar fi FireFox evident… nu!

    Si dupa ce ca bug-ul asta era foarte greu de remarcat oricum nu aparea decat in cateva cazuri speciale, motiv pentru care a si stat linistit un an jumatate.

    Written by Claudiu Persoiu

    14 February 2009 at 12:14 PM

    Internetul este pentru toata lumea dar nu pentru toate browserele?

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    Povestea incepe pe la inceputul Internetului, atunci cand WWW era inca la inceput, conexiunea se facea prin linii telefonice incete iar Mosaic facea furori. Dar a trecut mult timp de atunci, acum problema generala e cum sa faci o pagina web sa se miste ca o aplicatie Desktop si sa arate ca nimic altceva vazut pana acum. Dar cum unicitatea este doar o problema de timp iar aplicatile web nu vor ajunge niciodata cu adevarat aplicatii desktop nu are rost sa vorbesc despre asta.

    Problema este ca o data cu dezolvarea Web-ului tehnologiile au inceput sa fie confilctuale, iar cand spun asta nu ma refer la lucruri cum ar fi ca Microsoft nu a implementat <blink> in Internet Explorer sau ca <form> are margin in Internet Explorer iar in FireFox nu, ma refer la lucruri cu adevarat enervante, cum ar fi incompatibilitatile intre DOM din JavaScript si cel din JScript de la Microsoft. Unul din site-urile care mi se par bizar de incompatibile cu Internet Explorer este site-ul Ubuntu. in Internet Explorer in FireFox in FireFox

    Cand esti o distributie de renume cum e Ubuntu e usor de inteles de ce nu te preocupa compatibilitatea cu IE dar asta nu se aplica si in general. Nu poti pur si simplu sa te duci la un client si sa-i explici ca pe tine nu te intereseaza compatibilitatea cu un anumit browser pentru ca numarul clientiilor va scadea in mod dramatic. Acesta este si unul dintre motivele pentru care nuprea poti sa faci design sau programare JavaScript in linux, cel putin nu lucruri complexe fara sa testezi in Internet Explorer, cel putin partial.

    Din pacate se pare ca nici versiuniile Internet Explorer nu sunt tocmai compatibile intre ele, iar cum in acest moment cel mai folosit browser (in Romania) este Internet Explorer 6, urmat la mica distanta de Firefox 3 si Internet Explorer 7, la construirea unui site trebuie luate in calcul toate cele 3 versiuni.

    Problema cea mai mare este ca Web-ul acum nu mai este doar pentru sisteme Desktop si eventual cateva Laptop-uri de ultima generatie cum era cu ani in urma, acum exista sisteme cu diverse sisteme de operare, dispozitive mobile etc. De exemplu eu am pe telefonul mobil (HTC Touch Diamond) doua browsere in mod implicit, Internet Explorer si Opera 9.5 pentru mobil, diferentele sunt foarte mari si cu parere de rau Internet Explorer pentru mobil este deosebit de slab! Ca webdeveloper trebuie sa iei in calcul marea majoritate a dispozitivelor de pe piata, nu poti ignora un segment de piata si in special dispozitive de lux, acel segment de piata este foarte important pentru oricine.

    Din fericire toate aceste probleme se rezuma de cele mai multe ori la compatibilitatea dintre diferite versiuni de Internet Explorer si celelalte browsere care sunt in general surprinzator de compatibile intre ele. De exemplu eu testez aplicatile in general doar in Internet Explorer si FireFox pentru ca in general daca se comporta similar in cele doua se vor comporta similar si in Opera, Safari, Chrome si altele.

    Sa speram ca o data cu Internet Explorer 8 se vor mai reduce din problemele de incompatibilitate si pe segmentul de piata detinut de Microsoft si o data cu asta Internetul va redeveni nu doar pentru toata lumea ci si pentru toate browserele.

    Written by Claudiu Persoiu

    8 February 2009 at 2:00 PM