CODEWITHSUNDEEP
javascriptjquerycasting
rball
rball

Reputation: 6955

How do I add an integer value with javascript (jquery) to a value that's returning a string?

I have a simple html block like:

<span id="replies">8</span>

Using jquery I'm trying to add a 1 to the value (8).

var currentValue = $("#replies").text();
var newValue = currentValue + 1;
$("replies").text(newValue);

What's happening is it is appearing like:

81

then

811

not 9, which would be the correct answer. What am I doing wrong?

Upvotes: 95

Views: 276841

Answers (11)

Codemaker2015
Codemaker2015

Reputation: 1

You can use parseInt() method to convert string to integer in javascript

You just change the code like this

$("replies").text(parseInt($("replies").text(),10) + 1);

Upvotes: -1

rajeev
rajeev

Reputation: 21

Your code should like this:

<span id="replies">8</span>

var currentValue = $("#replies").text();
var newValue = parseInt(parseFloat(currentValue)) + 1;
$("replies").text(newValue);

Hacks N Tricks

Upvotes: 2

Ryan
Ryan

Reputation: 7951

You can multiply the variable by 1 to force JavaScript to convert the variable to a number for you and then add it to your other value. This works because multiplication isn't overloaded as addition is. Some may say that this is less clear than parseInt, but it is a way to do it and it hasn't been mentioned yet.

Upvotes: 1

Agorreca
Agorreca

Reputation: 686

Simply, add a plus sign before the text value

var newValue = +currentValue + 1;

Upvotes: 2

Gareth Nel
Gareth Nel

Reputation: 217

parseInt didn't work for me in IE. So I simply used + on the variable you want as an integer.

var currentValue = $("#replies").text();
var newValue = +currentValue + 1;
$("replies").text(newValue);

Upvotes: 12

Adeel Ishfaq
Adeel Ishfaq

Reputation: 11

var month = new Date().getMonth();
var newmon = month + 1;
$('#month').html((newmon < 10 ? '0' : '') + newmon );

I simply fixed your month issue, getMonth array start from 0 to 11.

Upvotes: 1

Diodeus - James MacFarlane
Diodeus - James MacFarlane

Reputation: 114367

parseInt() will force it to be type integer, or will be NaN (not a number) if it cannot perform the conversion. 

var currentValue = parseInt($("#replies").text(),10);

The second paramter (radix) makes sure it is parsed as a decimal number.

Upvotes: 189

Jon P
Jon P

Reputation: 19772

Parse int is the tool you should use here, but like any tool it should be used correctly. When using parseInt you should always use the radix parameter to ensure the correct base is used

var currentValue = parseInt($("#replies").text(),10);

Upvotes: 29

Bill Ortell
Bill Ortell

Reputation: 837

In regards to the octal misinterpretation of .js - I just used this...

parseInt(parseFloat(nv))

and after testing with leading zeros, came back everytime with the correct representation.

hope this helps.

Upvotes: 5

alex
alex

Reputation: 644

to increment by one you can do something like 

  var newValue = currentValue ++;

Upvotes: 2

Chuck
Chuck

Reputation: 237050

The integer is being converted into a string rather than vice-versa. You want:

var newValue = parseInt(currentValue) + 1

Upvotes: 29

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