<input type="image"> - HTML: Hypertext Markup Language
supported common attributes alt, src, width, height, formaction, formenctype, formmethod, formnovalidate, formtarget idl attributes none.
...t> elements, image button inputs support the following attributes: attribute description alt alternate string to display when the image can't be shown formaction the url to which to submit the data formenctype the encoding method to use when submitting the form data formmethod the http method to use when submitting the form formnovalidate a boolean which, if present, indicates that the form shouldn't be validated before submission formtarget a string indicating a browsing context from where to load the results of submitting the form height the height, in css pixels, at which to draw the image src the url from which to load the image width the width, in css pixels, at which to draw...
... formnovalidate a boolean attribute which, if present, specifies that the form should not be validated before submission to the server.
... formnovalidate html5 a boolean attribute specifying that the form is not to be validated when it is submitted.

HTMLButtonElement - Web APIs
htmlbuttonelement.formnovalidate is a boolean indicating that the form is not to be validated when it is submitted.
... the following attributes have been added: autofocus, formaction, formenctype, formmethod, formnovalidate, formtarget, labels, validity, validationmessage, and willvalidate.

HTMLInputElement - Web APIs
formnovalidate boolean: returns / sets the element's formnovalidate attribute, indicating that the form is not to be validated when it is submitted.
... the following properties have been added: autocomplete, autofocus, dirname, files, formaction, formenctype, formmethod, formnovalidate, formtarget, height, indeterminate, labels, list, max, min, multiple, pattern, placeholder, required, selectiondirection, selectionend, selectionstart, step, validationmessage, validity, valueasdate, valueasnumber, width, and willvalidate.

<input type="submit"> - HTML: Hypertext Markup Language
formnovalidate a boolean which, if present, means the form's fields will not be subjected to constraint validation before submitting the data to the server formtarget the browsing context into which to load the response returned by the server after submitting the form formaction a string indicating the url to which to submit the data.
... formnovalidate a boolean attribute which, if present, specifies that the form should not be validated before submission to the server.

<input>: The Input (Form Input) element - HTML: Hypertext Markup Language
m submission disabled all whether the form control is disabled form all associates the control with a form element formaction image, submit url to use for form submission formenctype image, submit form data set encoding type to use for form submission formmethod image, submit http method to use for form submission formnovalidate image, submit bypass form control validation for form submission formtarget image, submit browsing context for form submission height image same as height attribute for <img>; vertical dimension list almost all value of the id attribute of the <datalist> of autocomplete options max numeric types maximum value maxlength ...
... formnovalidate valid for the image and submit input types only.

HTML attribute reference - HTML: Hypertext Markup Language
formnovalidate <button>, <input> if the button/input is a submit button (type="submit"), this boolean attribute specifies that the form is not to be validated when it is submitted.

<button>: The Button element - HTML: Hypertext Markup Language
formnovalidate html5 if the button is a submit button, this boolean attribute specifies that the form is not to be validated when it is submitted.

<form> - HTML: Hypertext Markup Language
if this attribute is not set (and therefore the form is validated), it can be overridden by a formnovalidate attribute on a <button>, <input type="submit">, or <input type="image"> element belonging to the form.

<input type="range"> - HTML: Hypertext Markup Language
note: the following input attributes do not apply to the input range: accept, alt, checked, dirname, formaction, formenctype, formmethod, formnovalidate, formtarget, height, maxlength, minlength, multiple, pattern, placeholder, readonly, required, size, src, and width.