Replace all SVG images with inline SVG using jQuery

svg.js

/*
 * Replace all SVG images with inline SVG
 */
jQuery('img.svg').each(function(){
    var $img = jQuery(this);
    var imgID = $img.attr('id');
    var imgClass = $img.attr('class');
    var imgURL = $img.attr('src');

    jQuery.get(imgURL, function(data) {
        // Get the SVG tag, ignore the rest
        var $svg = jQuery(data).find('svg');

        // Add replaced image's ID to the new SVG
        if(typeof imgID !== 'undefined') {
            $svg = $svg.attr('id', imgID);
        }
        // Add replaced image's classes to the new SVG
        if(typeof imgClass !== 'undefined') {
            $svg = $svg.attr('class', imgClass+' replaced-svg');
        }

        // Remove any invalid XML tags as per http://validator.w3.org
        $svg = $svg.removeAttr('xmlns:a');

        // Replace image with new SVG
        $img.replaceWith($svg);

    }, 'xml');

});

and here is my take on it, in typescript, where it is unittestable
use it like this:
new InlineSvg().execute();

and add the class "svg-inline", to the svgs you want to inline

export default class InlineSvg {
    private imageElements: HTMLImageElement[];
    private svgElements: HTMLImageElement[];
    private classToReplace: string = "svg-inline";

    constructor() {
        this.imageElements = Array.from(document.querySelectorAll<HTMLImageElement>("img")) as HTMLImageElement[];
        this.svgElements = this.imageElements.filter((x: HTMLImageElement) =>x.classList.contains(this.classToReplace));
    }

    execute(): void {
        this.svgElements.forEach((x: HTMLImageElement) => {
            this.getSvg(x, x.src);
        });
    }

    replace(source: HTMLImageElement, target: HTMLElement): void {
        // add replaced image's ID to the new SVG
        if(typeof source.id !== "undefined") {
            target.id = source.id;
        }

        // add replaced image's classes to the new SVG
        source.classList.forEach((x: string) => {
            if(x===this.classToReplace) { return; }
            target.classList.add(x);
        });

        target.classList.add("replaced-svg");

        // remove any invalid XML tags as per http://validator.w3.org
        target.removeAttribute("xmlns:a");

        // replace image with new SVG
        source.replaceWith(target);
    }

    getSvg(source: HTMLImageElement, url: string): void {
        const http: XMLHttpRequest = new XMLHttpRequest();
        http.open("GET", url, true);
        http.setRequestHeader("Content-Type", "text/xml; charset=UTF-8");
        http.onload = () => {
            if(http.readyState === http.DONE && http.status === 200) {
                const target: HTMLElement = http.responseXML.documentElement;
                this.replace(source, target);
            }
        };
        http.send(null);
    }
}

Another simple but important addition could be to also get the replaced image's alt tag.

var imgAlt = $img.attr('alt');

// add replaced image's alt tag to the new SVG
if(typeof imgAlt !== 'undefined') {
        $svg = $svg.attr('alt', imgAlt);
}

@z1haze @engray I've adjusted the plain Javascript version to work with fetch.

document.querySelectorAll('img.svg').forEach((el) => {
      const imgID = el.getAttribute('id');
      const imgClass = el.getAttribute('class');
      const imgURL = el.getAttribute('src');

      fetch(imgURL)
          .then(data => data.text())
          .then(response => {
                const parser = new DOMParser();
                const xmlDoc = parser.parseFromString(response, 'text/html');
                let svg = xmlDoc.querySelector('svg');

                if (typeof imgID !== 'undefined') {
                    svg.setAttribute('id', imgID);
                }

                if(typeof imgClass !== 'undefined') {
                    svg.setAttribute('class', imgClass + ' replaced-svg');
                }

                svg.removeAttribute('xmlns:a');

                el.parentNode.replaceChild(svg, el);
          })
});

this code doesn't work on internet explorer any solution for this issue??

Great code btw, really useful.
If you need it in ES6:

   $('img.svg').each((i, e) => {

    const $img = $(e);

    const imgID = $img.attr('id');

    const imgClass = $img.attr('class');

    const imgURL = $img.attr('src');

    $.get(imgURL, (data) => {
        // Get the SVG tag, ignore the rest
        let $svg = $(data).find('svg');

        // Add replaced image's ID to the new SVG
        if (typeof imgID !== 'undefined') {
            $svg = $svg.attr('id', imgID);
        }
        // Add replaced image's classes to the new SVG
        if (typeof imgClass !== 'undefined') {
            $svg = $svg.attr('class', `${imgClass}replaced-svg`);
        }

        // Remove any invalid XML tags as per http://validator.w3.org
        $svg = $svg.removeAttr('xmlns:a');

        // Check if the viewport is set, if the viewport is not set the SVG wont't scale.
        if (!$svg.attr('viewBox') && $svg.attr('height') && $svg.attr('width')) {
            $svg.attr(`viewBox 0 0  ${$svg.attr('height')} ${$svg.attr('width')}`);
        }

        // Replace image with new SVG
        $img.replaceWith($svg);
    }, 'xml');
});

Thank you @VinceVachon, I found a small error here:
$svg = $svg.attr("class", ${imgClass}replaced-svg);

I added a space between the original classes and "replaced-img" new class:
$svg = $svg.attr("class", ${imgClass} replaced-svg);

While the plain JS version provided by @usame-algan gives me an error: "fetch(...) is undefined" and is not working for me...

Anyway thank everybody for contributing on this useful tool!

This is a great solution. Is there any way to use this with owl carousel? When new carousel items loading, those are not rendering to SVGs.

this code doesn't work on internet explorer any solution for this issue??

Yeah don't use Internet Explorer ;)