New Alpha Opera 12.00 for developers

Opera 12.00's new alpha build brought so much interesting with it that we decided to tell more about it. Links to the assembly can be found in the Desktop Team blog or wait a bit until it appears as an update for Opera Next . What interesting is this build for developers?

New opportunities

• XHR2 implementation completed (XMLHttpRequest2), in particular, Upload and Progress Events
• Now Opera supports the declarative “Do Not Track” header to ensure that sites do not track your activity, in more detail in English: Implementing the W3C

Manage transfer to <textarea>

When the white-space property with a value other than nowrap is used for <textarea> , Opera, like other browsers, continues to wrap text, regardless of the value set. However, we decided to change the described behavior in this assembly to take into account the applied styles. For example, you have the white-space: pre property for <textarea> - such text should be placed exactly as it was inserted into the field, i.e. take up only two lines.
Since we only support this, quite logical, behavior for <textarea> , we will need to take a closer look around for compatibility issues. If you find sites that break due to new behavior - tell us about it, for example on Twitter: @ODevRel_ru .

CSS bugs fixed

• A strange bug was corrected that led to the inverse of the background color for the block to which the currentColor value was applied, see the example of the block that is now blue, like in other browsers.
• When the list-style-image property refers to a regular picture in the presence of list-style-type: none , then the specified picture should become a bullet. Earlier, Opera did not draw this picture if it was created dynamically, like a CSS gradient, but now everything is in order: an example of using gradients to create bullet dynamically . Although few people know that in principle it is possible :)
• Previously, Opera calculated the shadow for the block and the text incorrectly. The specification says that the box-shadow property should be rendered as a Gaussian blur with a standard deviation equal to half the blur radius. Now Opera draws the shadow correctly both for blocks and for text: see the box-shadow comparison example with Gaussian blur in SVG .
• Text selection was not possible with line-height:0 and overflow:hidden . Now it is fixed.
• Opera usually ignored properties that follow the rule with !important at the end, but without a closing semicolon. This feature caused compatibility issues with many sites that had incorrect style rules. An excellent reason, by the way, to think about the validity of your code, khm-khm. See an example of how the incorrect use of !important affects the appearance of the text .
• While working on improving performance, we found and fixed a double-click bug that caused the element to stick to :active . See example sticking situation .
• The <style> tags in the SVG file embedded in the HTML5 document were previously ignored, but now they are not.
• The ability to remove the border-radius property using element.style.removeProperty now works as it should.

Work on various APIs

• The EventSource implementation has been updated so that Use Credentials defaults to false , in accordance with the latest specification update .
• The postMessage method now returns null , as indicated in the specification, and not file: //localhost , as before.
• By chance, the last download event in the FileReader API was called after the loadend event, but this has already been fixed.
• Event.prototype now supports constants : CAPTURING_PHASE , AT_TARGET , BUBBLING_PHASE , CAPTURING_PHASE , AT_TARGET , and BUBBLING_PHASE
• document.lastModified updated and returns the current time according to the specification.
• We noticed that working with the DOM, executing cloneNodes and assigning innerHTML causes excessive spikes in CPU activity on large pages like this . Now drawing such pages should take up much less CPU.

HTML5 forms

If the numeric value of the <input type="date"> element was hidden, set to zero, and then shown, the old value was still displayed, as in this example . The problem has been fixed.

And so on…

Empty page about: blank is not empty! Previously about: blank page looked like this:
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 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"> <html dir="ltr"> <head> <title>Blank page</title> <meta name="viewport" content="width=device-width,user-scalable=no"/> </head> <body></body> </html> 

Now the page contains only the most necessary, only what the HTML5 parser needs:

 <html><head></head><body></body></html> 

And what is called one more thing ™

The most curious of you, looking into the list of changes to the Presto engine, might have noticed the integration of packages 267-271 , or rather its second point. Nothing like that, just do not say that we did not warn you;)

Read more

• Labs blog on Dev.Opera with announcements of experimental releases, such as hardware acceleration, WebGL or getUserMedia to access the webcam.
• Desktop team blog with fresh test builds that will become the next releases
• Blog developers debugger Opera Dragonfly , which publishes all the changes and new experimental branches
• Twitter @ODevRel_ru news, tips, and even sometimes an insider for developers.