Modify a string in JavaScript

Question

I want to modify the color attribute that is returned in JQuery. So, lets assume the color is returned and is contained in a

var color
color = 'rgb(148, 141, 124)'

I want to modify the value of color to be:

color = 'rgb(148, 141, 124, .7)'

(in other words, insert the string ", .7")

• MarmiK: Just make the first tag like this color = 'rgba(148, 141, 124,1)' that will do the work easy for the next line.. color = 'rgba(148, 141, 124,.7)' just change last value from 1 to .7 :) and make sure RGB and RGBA are different only RGB works in some browser but some browser might not work!

Answer 1

Try,

var color = 'rgb(148, 141, 124)';
var newColor = color.slice(0,-1) + ",.7)"

DEMO

If you want it to be rgba then use,

var color = 'rgb(148, 141, 124)';
var newColor = (color.slice(0,-1) + ",.7)").split('(').join('a(');

DEMO

• Bill Criswell: It still needs the a in the rgba. OP forgot about that.

Answer 2

You could do like below:

color = color.replace(/\)/, ', 0.7)')

• Frank ZHENG: Yes,I am curious too.What's wrong with this expression?

Answer 3

Similar to above, slightly different method:

var color = 'rgb(148, 141, 124)';
var colorAlpha = color.replace(/rgb/g, 'rgba').replace(/\)/g, ', 0.7)');

FIDDLE

OR, as someone commented on the above, it could be simpler to add the alpha to the original variable, and just replace that number in the new string:

var color = 'rgba(148, 141, 124, 1.0)';
var colorAlpha = color.replace(/1.0/g, '0.7');
alert(colorAlpha);

• Justin: I guess I just wanted to temp the mysterious Captain Downvote. Success!

Answer 4

Using .split() also you can easily achieve your goal

var color = 'rgb(148, 141, 124)';
var newColor = color.split(")")[0];
alert(newColor + ', 0.7)');

DEMO