addition vs concatenation

[MandoThrasher]

I'm trying to add to numeric fields together, but it's concatenating the values instead of performing addition. I'm using the "+" operator.

i.e. 2 + 3 is returning 23

What am I doing wrong?

 

[jemminger]

this is probably because the original "numbers" are actually strings. use parseInt() to cast them as numbers:
[tt]
var a = "2";
var b = "3";

alert(parseInt(a, 10)+parseInt(b, 10))
[/tt]

note: use "10" as the second argument to parseInt() to ensure that it performs a base-10 cast.

there are other ways to achieve the same result, such as multiplying your strings by 1:
[tt]
var a = "2";
var b = "3";

alert((a * 1) + (b * 1))
[/tt]


=========================================================
while (!succeed) try();
-jeff

 

[TheConeHead]

or:

var a="10";
var b="35";
var c=Number(a)+Number(b);
alert(c);

 

[onpnt]

I cannot believe ther is not a FAQ for this. after the question ahs been answered more days then I've been alive.

anyone up to the task. we need it!!!!!!

if one is not posted in a hour or so I will ahve time to do it otehrwise please someone add one. unless I'm missing a exsisting one _________________________________________________________
for the best results to your questions: FAQ333-2924
_{01001111 01101110 01110000 01101110 01110100}

http://www.onpntwebdesigns.com

[/sub]

 

[MandoThrasher]

thanks!

 

[glendsj]

using the eval() method works too.
var a = 10;
var b = 5;
var c = eval(a) + eval(b);

 

[xutopia]

As usual Gary comes in with a Speed test!

My results! parseInt() is the winner being the most often on top in both Gecko Based Browsers (GBB) and in Internet Exploder.

Number() comes right behind at a negligeable time behind.

eval() comes in last taking about 10 times more time then our other concurrents. Though I did think of a way to make eval faster by calling it only once. Despite this it still comes in last. This is normal because eval calls a whole new JS interpreter to be loaded into memory.


<script>
var a = &quot;2&quot;, b = &quot;3&quot;, c, i = 10000;

var start = new Date();
var x = i;
while (x--)
{
c = parseInt(a) + parseInt(b);
}
var end = new Date();
document.writeln(&quot;<br>parseInt() \ttook &quot; + (end.getTime() - start.getTime())/i + &quot; milliseconds per round&quot

var start = new Date();
var x = i;
while (x--)
{
c = Number(a) + Number(b);
}
var end = new Date();
document.writeln(&quot;<br>Number() \ttook &quot; + (end.getTime() - start.getTime())/i + &quot; milliseconds per round&quot

var start = new Date();
var x = i;
while (x--)
{
c = eval(a) + eval(b);
}
var end = new Date();
document.writeln(&quot;<br>eval()\ttook &quot; + (end.getTime() - start.getTime())/i + &quot; milliseconds per round&quot

var start = new Date();
var x = i;
while (x--)
{
c = eval(a + &quot; + &quot; + b);
}
var end = new Date();
document.writeln(&quot;<br>special eval()\ttook &quot; + (end.getTime() - start.getTime())/i + &quot; milliseconds per round&quot
</script> Gary

http://www.xutopia.com

Haran