Webskew is the online version of Genskew.
When clicking the Browse button, a new window will appear in which you can select one or multiple files. To select gb or .gz files you will have to change the file type to all files in the appropriate dropdown menu. After pressing open, the selected file or files should be displayed below.
Next to the Browse button you can change the two nucleotides as well as the stepsize and windowsize and outputfiltype. The step and windowsize don't have to be specified and will be calculated automatically by dividing the sequence lenght by 1000 if left out. The step and windowsize are limited to 100. This is because if they are lower, there could be none of the specified nucleotides in the window and the formula used to calculate the skew would divide by 0.
Pressing the submit button will let you download the finished graph. If you have selected multiple graphs, they will be downloaded in a zip folder.