html – Page 2 – Make Me Engineer

Are single/double quotes allowed inside HTML attribute values?

Yes, both quotes are allowed in attribute values, but you must HTML-escape the quote you’re using as an attribute value delimiter, as well as other HTML-special characters like < and &: function encodeHTML(s) { return s.split(‘&’).join(‘&’).split(‘<‘).join(‘<’).split(‘”‘).join(‘"’).split(“‘”).join(‘'’); } var html=”<label my_attr=””+encodeHTML(attr_value)+'”>Text</label>’; However, you are usually much better off not trying to hack a document together from … Read more

Controlling image load order in HTML

Use Javascript, and populate the image src properties later. The # tells the browser to link to a URL on the page, so no request will be sent to the server. (If the src property was empty, a request is still made to the server – not great.) Assemble an array of image addresses, and … Read more

Change image in HTML page every few seconds

As I posted in the comment you don’t need to use both setTimeout() and setInterval(), moreover you have a syntax error too (the one extra }). Correct your code like this: (edited to add two functions to force the next/previous image to be shown) <!DOCTYPE html> <html> <head> <title>change picture</title> <script type = “text/javascript”> function … Read more

How to detect supported video formats for the HTML5 video tag?

You can check codecs for different video types with HTMLVideoElement.prototype.canPlayType. There is also a great HTML5 feature detection library, Modernizr. var testEl = document.createElement( “video” ), mpeg4, h264, ogg, webm; if ( testEl.canPlayType ) { // Check for MPEG-4 support mpeg4 = “” !== testEl.canPlayType( ‘video/mp4; codecs=”mp4v.20.8″‘ ); // Check for h264 support h264 = … Read more

calculate the number of html checkbox checked using jquery

There are multiple methods to do that: Method 1: alert($(‘.checkbox_class_here:checked’).size()); Method 2: alert($(‘input[name=checkbox_name]’).attr(‘checked’)); Method: 3 alert($(“:checkbox:checked”).length);

Why is a self-closing iframe tag preventing further DOM elements to be displayed?

Because the iframe element isn’t a self-closing element. The versions of Firefox and Safari you’re using are treating the /> at the end as just > and assuming everything after it is contained within the iframe. If we attempt to pass the code you’ve given through W3C’s validator we’ll see the following errors: Error: Self-closing … Read more

Set default value for a input file form [duplicate]

From HTMLHelp.com : The file input type creates a field through which users can upload files from their local computer or network. The VALUE attribute specifies the name of the initial file, but it is typically ignored by browsers as a security precaution. Therefore, setting an initial value is not supported.

Directly reference HTML elements [duplicate]

Being able to select elements on the page based on their [id] is a “feature” from early JavaScript (DOM lvl 0 or 1 methinks, can’t seem to find the source). Unfortunately it’s a temperamental feature. What would happen if you had: <div id=”window”></div> or <div id=”document”></div> Better yet, what happens here? <div id=”foo”></div> <div id=”bar”></div> … Read more

Is the HTML shown via ‘View Source’ different from the HTML shown in (Firebug) developer tools?

Yes they are different. View source shows you the original HTML source of the page. The inspector shows you the DOM as it was interpreted by the browser. This includes for example changes made by javascript which cannot be seen in the HTML source. Oh and this also counts for the developer tools that allow … Read more

multiple selections with datalist

Multiple currently working only with input type=”email” and only in Chrome and Opera Look at this minimalist example: input{width:500px} <input type=”email” list=”emails” multiple> <datalist id=”emails”> <option value=”first@example.com”> <option value=”second@example.com”> <option value=”third@example.com”> <option value=”last@example.com”> </datalist> <br><br><br> <input type=”text” list=”texts” multiple> <datalist id=”texts”> <option value=”black”> <option value=”gold”> <option value=”grey”> <option value=”pink”> <option value=”turquoise”> <option value=”red”> <option value=”white”> … Read more

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