Add 1000 to 100 to display 1100

[heldenbrau]

I have a variable which is 100 and I want to add 1000 to it making 1100

tbox$count.value = change$count+1000;

It give the following 1001000

 

What do I need to do to make it display 1100?

[kicken]

You need to convert your change$count variable to a number before you can add it. A quick way to do this is to just prefix it with a +.

 

tbox$count.value = (+change$count)+1000;

[heldenbrau]

Thanks loads, that worked.  Should have asked here an hour ago instead of looking up all this parseInt stuff that didn't make any sense.

[.josh]

well, the + prefix is a shortcut. You could have alternatively done

 

tbox$count.value = parseInt(change$count)+1000;

or even

 

tbox$count.value = Number(change$count)+1000;

The overall takeaway here is that wherever you got change$count from (e.g. grabbing from some form field, receiving an ajax response, etc.), the value was stored as some other type (probably string). So you were basically doing "100"+1000 which javascript interprets as string concatenation.

 

So there are ways (shown above) to convert the value to another variable type (type casting), in order to ensure javascript does what you expect it to do. It is actually one of those best things to check (you can use the typeof operator to check variable type) and/or convert variable type before performing operations, to ensure expected results.