Ignore Last Digit

This is the code I am currently using to display the result for:

Should be calculated in a new field as 1.2345 - 1.2343 (the two and the 7 are dropped off, respectively).

Where Entry Sunday1 is 1.23452

Where Exit Sunday1 is 1.23437

This code drops the last digit and works correctly if the last digit is 5 numbers below (for example if the last digit "7" was a "6").

var BuySell = this.getField("BuySell Sunday1").valueAsString;

var val = this.getField("Entry Sunday1").valueAsString;

var countDecimals = function(value) {

    if (Math.floor(value) !== value)

        return value.toString().split(".")[1].length || 0;

    return 0;

}

countDecimals(val);

if(BuySell == "Buy")event.value = ( this.getField("Exit Sunday1").value - this.getField("Entry Sunday1").value );

if(BuySell == "Sell")event.value = ( this.getField("Entry Sunday1").value - this.getField("Exit Sunday1").value );

if (countDecimals(val) == "3")event.value =  event.value("Exit Sunday1").value* "100";

if (countDecimals(val) == "4")event.value = event.value("Exit Sunday1").value * "1000";

if (countDecimals(val) == "5")event.value = event.value * "10000";

if(event.value >= 0)  

    event.target.textColor = color.blue;

else    

    event.target.textColor = color.red;

event.value = parseFloat(event.value).toFixed(0);