Frequently Asked Questions

How do I share a diff?

There are two ways to share your diff result with other people:

What is folding?

Folding is a term that refers to the ability of a diff tool to collapse and expand groups of lines that are identical between the two files being compared. includes this folding features as can be seen below. In the figure on the left, several lines between the two files match exactly, and so the tool collapses those lines, stating that they are identical. When the user clicks on the "+" symbol next to that line, the matching lines (6 in this case) expand out to show the contents (figure on the right).

collapsed lines expands to... expanded lines

Notice how the folded lines don’t include all the matched lines in the section (i.e., in depicted example there are 6 additional matching lines after the folded group). The folding feature will leave several matching lines as-is before and/or after the folded group to give better context of what the folded group contains.

What is scrollbar binding?

When you are viewing a diff result between two files, scrollbar binding makes it so that when you scroll in one file, the other file will automatically scroll to the same point. This is extremely helpful in keeping track of which lines in one file correspond to the lines in the other file. This option is turned on by default, but can be disabled by unchecking the “Bind scrollbars together” option at the top of the diff result web page.

How do I embed diff results in a web site or forum?

Embedding diff results into another website can be extremely helpful when you want to provide a visual context of differences between files – whether your purpose is to provide code-change insights on a blog or providing coding help on a forum. provides the ability to embed your diff results in another website. You can do this by including an iframe that references src="", where you replace “your-id-here” with the diff result ID from the results page. You can get the iframe code by clicking on the “share” button below the diff result that you want to embed. Here is an example of the iframe code:

<iframe src="" frameBorder="0" seamless="seamless" scrolling="no" style="width: 100%; height: 35em;"></iframe>

… which gives the following embedded diff:

Embedding Options

Note that there are additional customization options you can pass with the URL, by appending them as &nojs, &noopt, &noname, and &wtxt at the end of the URL (after the diff ID). These options are:

  • &nojs – Retrieves a version of the diff that does not rely on JavaScript to be displayed correctly. It is recommended to use the normal JavaScript-based version.
  • &noopt – Removes the checkbox options at the top of the diff.
  • &noname – Removes the file names at the top of each diff.
  • &wtxt – Changes the text color from black to white for the header and footer of the diff. This is useful if you want to embed the diff on a web page that has a dark background color.

For example, to embed the diff as an iframe with javascript disabled and using white text for the header and footer, this would be the code:

<iframe src="" frameBorder="0" seamless="seamless" scrolling="no" style="width: 100%; height: 35em;"></iframe>

Note that some 3rd-party websites might not allow entering iframe tags in your message post. They are correct to prohibit the use of iframes in general cases, for security reasons. However, most 3rd-party websites can also grant exceptions to allow iframes for specific websites (like If you have found a website where you need to embed your diff result, but the website doesn’t allow embedding iframes from, then feel free to ask them to allow this exception.

How do diff two PDF files?

Comparing the text in two PDF files is very valuable, but is typically difficult to do without special tools. will extract the text from the PDF files for you, which you can then subsequently edit if you want to before submitting for comparison. To do this, simply select the desired PDF file either by dragging and dropping into the input text area or by clicking the attachment insertion icon and selecting the desired PDF file from the file selection popup. After selecting the file, will automatically start extracting the text and will automatically copy the text into the input text box for you.

How do I diff webpage sources?

Being able to compare the source code between two different URLs is a very important feature for web developers. Any given webpage may have so many lines of code that it can make it very difficult for the web developer to look for problems in one page’s source code that aren’t present in another page. The developer doesn’t want to have to always be copying and pasting the pages’ generated source code into local documents that they then have to do a diff on, since this ends up being a tedious task. supports providing the URLs, which it then loads the generated source code automatically from those web pages and performs the diff comparison between them.

To use this feature, simply enter the URLs to compare in the text fields at The tool will automatically detect that they are URLs (as opposed to regular non-URL copied/pasted text), will download the generated page source code and provide the diff.

How do I report a bug or feature request?

Please submit all FileDiff bug reports or feature requests through our FileDiff Google+ community.