Via javascript, I want to generate the percentage plete between these two days based on today and I will use this percentage on a jQuery UI progress bar to indicate the time plete or left.

I have tried this formula but I end up always getting 100:

Assume I have two dates:

start = new Date(2012,6,2); // Jul 02 2012
end = new Date(2012,6,8); // Jul 08 2012
today = new Date();

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

How can I achieve this correctly?

Via javascript, I want to generate the percentage plete between these two days based on today and I will use this percentage on a jQuery UI progress bar to indicate the time plete or left.

I have tried this formula but I end up always getting 100:

Assume I have two dates:

start = new Date(2012,6,2); // Jul 02 2012
end = new Date(2012,6,8); // Jul 08 2012
today = new Date();

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

How can I achieve this correctly?

• javascript
• datetime
• progress-bar

• 2 Why bother to instantiate dates at all? Just use those raw numbers, and then get the current time from your current date with .getTime() – Pointy Commented Jul 6, 2012 at 13:39
• I just get these numbers in Unix timestamp from my server, actually you can ignore the initiation example dates. – Hellnar Commented Jul 6, 2012 at 13:41
• Just fixed the example time instantiates. – Hellnar Commented Jul 6, 2012 at 13:43
• @Hellnar the ments don't match the code. – EricG Commented Jul 6, 2012 at 13:45
• @EricG Thank you Eric, fixed code according to the ment. – Hellnar Commented Jul 6, 2012 at 13:47

3 Answers 3

Since you get unix timestamps from server, you can just do this

var start = 1341201600 * 1000,
    end = 1341720000 * 1000,
    now = +new Date;

Math.round(( ( now - start ) / ( end - start ) ) * 100) + "%" //73%

I took the liberty to adjust the ment.

var start = new Date(2012,6,2); // Jul 02 2012
var end = new Date(2012,8,2); // Sep 02 2012
var today = new Date();

var total = end - start;
var progress = today - start;

console.log( Math.round(progress/ total * 100 ) + "%" );

Yields 8% [ 6th of July ]

Your formula should be

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