Safe HTML Attributes include: align, alink, alt, bgcolor, border, cellpadding, cellspacing, class, color, cols, colspan, coords, dir, face, height, hspace, ismap, lang, marginheight, marginwidth, multiple, nohref, noresize, noshade, nowrap, ref, rel, rev, rows, rowspan, scrolling, shape, span, summary, tabindex, title, usemap, valign, value, vlink, vspace, width. But if youre not sure, include alt text just in case. If you're using JavaScript to construct a URL Query Value, look into using window.encodeURIComponent(x). These attributes, introduced by Netscape, were ones that the W3C (World Wide Web Consortium) adopted in 1996 for the HTML 3.2 specification. When looking at XSS (Cross-Site Scripting), there are three generally recognized forms of XSS: The XSS Prevention Cheatsheet does an excellent job of addressing Reflected and Stored XSS. Frameworks make it easy to ensure variables are correctly validated and escaped or sanitised. Try to refactor your code to remove references to unsafe sinks like innerHTML, and instead use textContent or value. Always JavaScript encode and delimit untrusted data as quoted strings when entering the application as illustrated in the following example. Returns a boolean value that is true if the browser has finished fetching the image, whether successful or not. Encode all characters with the %HH encoding format. A buffer space would be nice, and thats where HSPACE and VSPACE come into play. However, frameworks aren't perfect and security gaps still exist in popular frameworks like React and Angular. word-break attribute, using the break-all value to tell the The Marquee loop attribute in HTML is used to define the number of time marquee should loop. the URL selected by the browser from the srcset. Here are some examples of encoded values for specific characters. An example of a fully formed HTML IMG tag looks like this: The only attribute you need to get an image to display on a web page is the src attribute. Other CSS Contexts are unsafe and you should not place variable data in them. The HTMLImageElement property In other words, add a level of indirection between untrusted input and specified object properties. characters, other than the whitespace separating the URL and the corresponding condition The default value is INFINITE, which means that the marquee loops endlessly. In these cases, HTML Sanitization should be used. Specifies the amount of whitespace to be inserted above and below the image (in pixels). An optional string representing a hint given to the browser on how it should prioritize fetching of the image relative to other images. This specifies the width of the marquee. This specifies the type of scrolling of the marquee. Additionally, avoid duplicating the alt attribute's value in a title attribute declared on the same image. Use the margin CSS property instead. XSS is serious and can lead to account impersonation, observing user behaviour, loading external content, stealing sensitive data, and more. The number of pixels of white space on the left and right of the image. Ensuring that all variables go through validation and are then escaped or sanitized is known as perfect injection resistance. Each source size consists of: : One or more strings separated by commas, indicating possible image sources for the. It is important to use an encoding library that understands which characters can be used to exploit vulnerabilities in their respective contexts. You must regularly patch DOMPurify or other HTML Sanitization libraries that you use. The value you choose also will determine how the adjoining text flows around the image if the graphic is included in a block element, such as a paragraph
, or in a headline, such as