svgedit/archive/untested-extensions/ext-server_opensave/ext-php_savefile.js

// TODO: Might add support for "exportImage" custom
//   handler as in "ext-server_opensave.js" (and in savefile.php)

export default {
  name: 'php_savefile',
  init () {
    const svgEditor = this;
    const {
      canvas: svgCanvas
    } = svgEditor;
    /**
     * Get file name out of SVGEdit document title.
     * @returns {string}
     */
    function getFileNameFromTitle () {
      const title = svgCanvas.getDocumentTitle();
      return title.trim();
    }
    const saveSvgAction = './savefile.php';
    svgEditor.setCustomHandlers({
      save (win, data) {
        const svg = '<?xml version="1.0" encoding="UTF-8"?>\n' + data;
        const filename = getFileNameFromTitle();

        // $.post(saveSvgAction, { output_svg: svg, filename });
        const postData =  { output_svg: svg, filename };
        fetch(saveSvgAction, {
          method: "POST",
          body: JSON.stringify(postData)
        }).then( (res) => {
          return res;
        })
          .catch( (error) => { console.info('error =', error);});
      }
    });
  }
};