Formaction/formtarget polyfill

form-poly.js

var _input = document.createElement('input');

if ( ! ('formTarget' in _input && 'formAction' in _input)) {
    $('[type="submit"]').on('click', function (e) {
        // Prevent default form submit
        e.preventDefault();
        
        // Find parent form and store values
        var $this = $(this),
            $form = $this.closest('form'),
            formTarget = $form.attr('target'),
            formAction = $form.attr('action');
        
        
        // Check if a target is defined and set the form target accordingly
        if ($this.attr('formtarget') !== null)
            $form.attr('target', $this.attr('formtarget'));
        
        // Check if an action is defined and set the form action accordingly
        if ($this.attr('formaction') !== null)
            $form.attr('action', $this.attr('formaction'));
        
        // Submit form
        $form.submit();
        
        // Set form back to initial values
        $form.attr('target', formTarget);
        $form.attr('action', formAction);
    });
}