Basic JavaScript Function Issue

Question

Ok, so I am trying to call the convert function in the calculate_drug function but the final "sotp" "start" alert keeps coming up as undefined. I am assuming this is because it thinks convert is not defined. This is a python code I'm trying to convert to JS and I'm obviously not very familiar with JS.

What am I doing wrong here?

<!DOCTYPE html>
<html>
<head>
</head>
<body>
<p>Click the button</p>
<button onclick="calculate_drug()">Drug</button>


<script>

function convert(time)
{
minutes = time.substr(-2)
hours = Math.floor(time/100)
con_time = (hours * 60) + parseInt(minutes)
}

function calculate_drug(start, stop)
{
start = prompt("Enter Start Time")
stop = prompt("Enter Stop Time")
start = convert(start)
alert(start)
stop = convert(stop)
alert(stop)
}

</script>
</body>
</html>

@Geo Doesn't need to, though; there are parameters that are promptly read in via a prompt. It's weird, but there it is. — Dave Newton
– Dave Newton, Commented Apr 25, 2014 at 3:40
@DaveNewton True. I didn't read the whole thing before replying. I posted an answer to the question that is actually working though :) — Geo
– Geo, Commented Apr 25, 2014 at 3:50

xdazz · Accepted Answer · 2014-04-25 03:38:11Z

2

You missed the return, so the result is always undefined.

And note variables without var declaration are treated as global variables, which is highly not recommended.

answered Apr 25, 2014 at 3:38

xdazz

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Comments

ggutenberg · Accepted Answer · 2014-04-25 03:38:45Z

0

You need to return something from the convert function.

function convert(time)
{
    minutes = time.substr(-2)
    hours = Math.floor(time/100)
    con_time = (hours * 60) + parseInt(minutes)
    return con_time;
}

answered Apr 25, 2014 at 3:38

ggutenberg

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Comments

Adam W · Accepted Answer · 2014-04-25 03:41:15Z

0

I'm not js expert but almost all my java scripts look like this:

<script>
$(document).ready(function () {
    console.log("js kicked");
    $("#req").addClass("active open");
    $("#req-history").addClass("active");
});

answered Apr 25, 2014 at 3:41

Adam W

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1 Comment

Jamie Over a year ago

Sir, this is jQuery, and the thing he is using is plain javascript.

Gian Carlo · Accepted Answer · 2014-04-25 03:42:25Z

0

You forgot to return a value

function convert(time)
{
    minutes = time.substr(-2)
    hours = Math.floor(time/100)
    con_time = (hours * 60) + parseInt(minutes)

    return con_time;
}

answered Apr 25, 2014 at 3:42

Gian Carlo

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Comments

Geo · Accepted Answer · 2014-04-25 03:49:11Z

0

Try this :

 function convert(time)
        {
            var minutes = time.substr(-2);
            var hours = Math.floor(minutes/100);
            var con_time = (hours * 60) + parseInt(minutes);

            return con_time;
        }

        function calculate_drug()
        {

            var startTime = prompt("Enter Start Time");

             var stopTime = prompt("Enter Stop Time");
            startTime = convert(startTime);
             alert(startTime);
            stopTime = convert(stopTime);
             alert(stopTime);
        }

answered Apr 25, 2014 at 3:49

Geo

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