JavaScript calculate with viewport width/height

Question

I am trying to set a responsive point in my mobile Webview and did this:

var w = window.innerWidth-40;
var h = window.innerHeight-100;

This works great so far. But the values -40 and -100 are not in the viewport scaling height and width.

When I do this:

var w = window.innerWidth-40vw;
var h = window.innerHeight-100vh;

as it should be to stay responsive and relative to the viewport - the JS does not work anymore. I think vh and vw works only in CSS ? How can I achieve this in JS ?

Pleas no JQuery solutions - only JS!

Thanks

Answer 1

Based on this site you can write following function in javascript to calculate your desired values:

function vh(v) {
  var h = Math.max(document.documentElement.clientHeight, window.innerHeight || 0);
  return (v * h) / 100;
}

function vw(v) {
  var w = Math.max(document.documentElement.clientWidth, window.innerWidth || 0);
  return (v * w) / 100;
}

function vmin(v) {
  return Math.min(vh(v), vw(v));
}

function vmax(v) {
  return Math.max(vh(v), vw(v));
}
console.info(vh(20), Math.max(document.documentElement.clientHeight, window.innerHeight || 0));
console.info(vw(30), Math.max(document.documentElement.clientWidth, window.innerWidth || 0));
console.info(vmin(20));
console.info(vmax(20));

I used this incredible question in my codes!

Answer 2

Try this:

function getViewport() {

 var viewPortWidth;
 var viewPortHeight;

 // the more standards compliant browsers (mozilla/netscape/opera/IE7) use window.innerWidth and window.innerHeight
 if (typeof window.innerWidth != 'undefined') {
   viewPortWidth = window.innerWidth,
   viewPortHeight = window.innerHeight
 }

// IE6 in standards compliant mode (i.e. with a valid doctype as the first line in the document)
 else if (typeof document.documentElement != 'undefined'
 && typeof document.documentElement.clientWidth !=
 'undefined' && document.documentElement.clientWidth != 0) {
    viewPortWidth = document.documentElement.clientWidth,
    viewPortHeight = document.documentElement.clientHeight
 }

 // older versions of IE
 else {
   viewPortWidth = document.getElementsByTagName('body')[0].clientWidth,
   viewPortHeight = document.getElementsByTagName('body')[0].clientHeight
 }
 return [viewPortWidth, viewPortHeight];
}

Reference: http://andylangton.co.uk/articles/javascript/get-viewport-size-javascript/