Calculate percentage between two dates in JavaScript

Question

I've been trying to calculate the percentage between two dates given the code from some questions here in StackOverflow but the code doesn't work correctly. This is the question: Get the percent of time elapsed between two javascript dates

var start = new Date(2015,6,1),
end = new Date(2015,12,1),
today = new Date();

alert(Math.round(( ( today - start ) / ( end - start ) ) * 100) + "%");

I want to calculate the progress from the 1rst of june to the 1rst of december and I get "-7"

Please help! Thanks

Answer 1

 var start = new Date(2015,6,1),
 end = new Date(2015,11,1),
 today = new Date();

 //use Math.abs to avoid sign
 var q = Math.abs(today-start);
 var d = Math.abs(end-start);
 alert("Rounded: "+Math.round((q/d)*100) + "%");
 alert("Fraction: "+((q/d)*100) + "%");

Also read Ray Toal answer 6 is july not jun