javascript replace not workings

Question

I've got a problem with replace not working.

alert($('input#membership_edc').next("label").html().replace(/£/g, ""));

The value of the label after the input would be 24ドル.00, but I want to do a math on that value then put it back with the new value. It's not removing the pound sign.

What's wrong? Thanks.

• user1150525: Just a note: you can use replace("£", "")
• T.J. Crowder: "It's not removing the pound sign." Not removing it where? It won't be shown in the alert, you're definitely removing it from the string you pass to alert (proof). That doesn't change anything else.
• David Thomas: What are you trying to do, why are you removing the £ in the first place?
• rucsi: as I've said here: stackoverflow.com/a/10176894/643580, the code is working. you must have a markup or a script error elsewhere.

Answer 1

To read/modify/write use the function parameter version of .html():

$('input#membership_edc').next("label").html(function(index, old) {
 var n = parseFloat(old.replace('£', '');
 return n + 10;
});

would replace '24ドル.00' with '34'.

• Felix Kling: I don't think the OP want's the replace the HTML (at least not the pound sign)... he just wants to extract the numeric value to perform calculations. edit: as it seems he want to put the changed value back, this could still be useful.
• Felix Kling: I think you mean var n = parseFloat(old); or simply var n = +old.replace('£', '');. Strings don't have a parseFloat method.
• Alnitak: @FelixKling duh, yes... (blush)
• i-CONICA: I think I've found the error. If I view the pound sign in the source, it's not a pound sign, it's a "miss-matched character set" question mark. I can't replace the string I'm finding with £ then search for that, though. :( I get NaN when I run that code above.
• Alnitak: @i-CONICA Try using '\xa3` instead of the £ symbol

Answer 2

You need to set the value returned from the replace. Try below,

var $label = $('input#membership_edc').next("label");
$label.html($label.html().replace(/£/g, ""));

• Felix Kling: I don't think the OP want's the replace the HTML... he just wants to extract the numeric value to perform calculations.
• i-CONICA: Correct Felix, I just want the numeric value so that I can perform a mathematical operation on it, then put it back modified.
• Selvakumar Arumugam: @i-CONICA I see, Check the fiddle posted by stackoverflow.com/a/10176894/297641 seems to work. Check for any script error.

Answer 3

Nothing wrong. It is working here. Are you sure your markup is fine?

Answer 4

The string replace function returns a new string. Strings themselves are immutable in javascript, I think. As Vega has it:

// avoid looking this up twice
var label = alert($('input#membership_edc').next("label"); 
// replace and assign
label.html(label.html().replace(/£/g, ""));

Edit:

To get the numerical value from the string:

var amount = alert($('input#membership_edc').next("label").html().match(/£\s*([-0-9.]+)/)[1];

This matches the numbers etc after the £ (ignoring whitespace), and uses index 1 from the array, containing the contents of the first group match (in the brackets).

" 1ドル.45".match(/£\s*([-0-9.]+)/)[1]; // returns "1.45"

Beware that it is still a string, so you might want to do parseFloat on it.

• Selvakumar Arumugam: Seems like that is not what OP wants.. see the comments in my answer.