Bitwise OR operator

A bitwise or operator can be used to truncate floating point figures and it works for positives as well as negatives:

function float2int (value) {
    return value | 0;
}

Results

float2int(3.1) == 3
float2int(-3.1) == -3
float2int(3.9) == 3
float2int(-3.9) == -3

Performance comparison?

I've created a JSPerf test that compares performance between:

• Math.floor(val)
• val | 0 ^{bitwise OR}
• ~~val ^{bitwise NOT}
• parseInt(val)

that only works with positive numbers. In this case you're safe to use bitwise operations well as Math.floor function.

But if you need your code to work with positives as well as negatives, then a bitwise operation is the fastest (OR being the preferred one). This other JSPerf test compares the same where it's pretty obvious that because of the additional sign checking Math is now the slowest of the four.

Note

As stated in comments, BITWISE operators operate on signed 32bit integers, therefore large numbers will be converted, example:

1234567890  | 0 => 1234567890
12345678901 | 0 => -539222987

This works:

var currencyString = "£" + (amount/100).toFixed(2);

Just adding that toFixed() will return a string value, so if you need an integer it will require 1 more filter. You can actually just wrap the return value from nnnnnn's function with Number() to get an integer back:

function insertDecimal(num) {
   return Number((num / 100).toFixed(2));
}

insertDecimal(99552) //995.52
insertDecimal("501") //5.01

The only issue here is that JS will remove trailing '0's, so 439980 will return 4399.8, rather than 4399.80 as you might hope:

insertDecimal(500); //5

If you're just printing the results then nnnnnn's original version works perfectly!

notes

JavaScript's Number function can result in some very unexpected return values for certain inputs. You can forgo the call to Number and coerce the string value to an integer by using unary operators

return +(num / 100).toFixed(2);

or multiplying by 1 e.g.

return (num / 100).toFixed(2) * 1;

TIL: JavaScript's core math system is kind of weird

In javascript you can try with using Number() function to convert a string to a number (integer or decimal) if needed, and you can use parseFloat(number) method.

Examples on using Number():

// Convert strings
Number('123'); // returns 123
Number('12.3'); // returns 12.3
Number('3.14someRandomStuff'); // returns NaN
Number('42px'); // returns NaN

Examples on using parseFloat():

var text = '3.14someRandomStuff';
var pointNum = parseFloat(text);
// returns 3.14

In your particular case however, this is how it could work as an example: (Edited, updated code, using the OP's code, since I had a little more time now to clear this for later, useful reference)

<?php
$total_count = (string) "£3,400.00";
$total_commission = (string) "£3,500.25";
$active_refs = (string) "£4,400.87";
?>

<div class="container2">
  <div id="value1"></div>
  <div id="value2"></div>
  <div id="value3"></div>
</div>

<script>  

// getting a float number from a formatted PHP string
var getNum = function (str) {
    var num = str.replace(/[\£\,]/mg, '');
    var num2 = parseFloat(num);
    return num2;
}

// converting the counter value back to a currency format
var convertNum = function(number){
    let numb = number;
    return numb.toLocaleString('en-GB', {style : 'currency', currency : 'GBP', minimumFractionDigits : '2', currencyDisplay : 'symbol'});
}

var value1 = getNum("<?php echo (string) $total_count ?>");
var value2 = getNum("<?php echo (string) $total_commission ?>");
var value3 = getNum("<?php echo (string) $active_refs ?>");

// Count Up
function animateValue(id, start, end, duration) {
    var obj = document.getElementById(id);
    var range = end - start;
    var minTimer = 50;
    var stepTime = Math.abs(Math.floor(duration / range));
    // never go below minTimer
    stepTime = Math.max(stepTime, minTimer);
    // get current time and calculate desired end time
    var startTime = new Date().getTime();
    var endTime = startTime + duration;
    var timer;

  function run() {
      var now = new Date().getTime();
      var remaining = Math.max((endTime - now) / duration, 0);
      var value = parseFloat(end - (remaining * range));
      obj.innerHTML = convertNum(value);
      if (value == end) {
          clearInterval(timer);
      }
  }

  timer = setInterval(run, stepTime);
  run();

}

animateValue("value1", 1, value1, 1750);
animateValue("value2", 1, value2, 1750);
animateValue("value3", 1, value3, 1750);

</script>

And you can also check the result/output of the above code version here: or if it was deleted already, then here

And maybe less importantly I’d like to point out that in your code the following line converted the decimal to integer which had to be edited too:

var value = Math.round(end - (remaining * range));

This one line would return back an integer number.