Ajustar zoom al ancho de la pantalla (jquery / vanilla)

jquery.js

jQuery(document).ready(function($){
  
 nsZoomZoom(); 
  
 $( window ).resize(function() { 
   nsZoomZoom();
 });
  
  
 function nsZoomZoom() {
    htmlWidth = $('html').innerWidth();
    bodyWidth = 1000;
   
    if (htmlWidth < bodyWidth)
       scale = 1
    else {
       scale = htmlWidth / bodyWidth; 
    }
 
    // Req for IE9
    $("body").css('-ms-transform', 'scale(' + scale + ')');
    $("body").css('transform', 'scale(' + scale + ')');
 } 
    
});

styles.css

body {
    position: absolute;
    left: 25%;
    top: 100%;
}

vanilla.js

var trasweb = {};

trasweb.getSize = function () {
    var w = window,
        d = document,
        e = d.documentElement,
        g = d.getElementsByTagName('body')[0],
        x = w.innerWidth || e.clientWidth || g.clientWidth,
        y = w.innerHeight || e.clientHeight || g.clientHeight;

    return {"x": x, "y": y};
};

function zoom_trasweb() {
    var window_width = document.documentElement.clientWidth;
    var body_width = document.getElementsByTagName('body')[0].childNodes[0].clientWidth + 100;
    if (window_width <= body_width) {
       var  scaleX = 1;
       var  scaleY = 1;
    }else {
       var  scaleX = window_width / body_width;
        console.log(window_width, body_width, scaleX);

        var window_height = document.documentElement.clientHeight;
        var body_height = document.getElementsByTagName('body')[0].childNodes[0].clientHeight;

        if(window_height < body_height) {
            var  scaleY = body_height / window_height;
        }else {
            var  scaleY = window_height / body_height;
        }
        console.log(window_height, body_height, scaleY);

    }

    document.body.style['transform'] = 'scale(' + scaleX + ', ' + scaleY+ ' )';
    if(scaleX !== 1 ) {
        var margin_top = body_height * scaleY;
        console.log(margin_top);
    }

}