textarea resize: none

#foo { resize: none; } Note that this is only relevant for WebKit-based browsers (i.e., Safari and Chrome), which add the resize handle to TextArea controls. textarea { resize: none; } Styling valid and invalid values. none: the element is not resizeable. both: the user can resize the element’s height and/or width. those within, and outside the bounds set by minlength, maxlength, or required) can be highlighted using the :valid and :invalid pseudo-classes. This property will also hide the resizing handle at the bottom-right corner of the textarea. This both are the example of where HTML TextArea Input … They come with a default resize property, and we can turn this off by using the following code: textarea {resize: none;} You … I admit I also opened the DevTools to override the resize: none declaration but that’s not really a productive way to do things. Just drag this handle to resize the textarea in vertically and horizontally. In the bottom right corner you can see the grabber handle. Is there a setting in about:config or an add-on to disable this for some/all websites? Maybe your script could be only to resize bigger, and not smaller? You could argue it makes sence to either add textarea{ resize: none; } to your css, or add something that turns the feature off when the user uses the manual resize of pulling the corner of the textarea. Allowable values self-explanatory: none (disables textarea resizing), both, vertical and horizontal. Valid and invalid values of a