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Howie Yeo
Courses Plus Student 3,639 Pointswhy are we adding so many + operator in $(“#newColor”).css(“background-color”, "rgb("+r+","+g+","+b+")"
function changeColor() {
var r = $("#red").val();
var g = $("#green").val();
var b = $("#blue").val();
$("#newColor").css("background-color", "rgb(" + r + "," + g +", " + b + ")");
}
Can anyone explain why the above is rgb(value) is written in such a way that there is so many + sign? Why not : rgb("r", "g", "b") since its already separated by a COMMA ?
1 Answer
Erik McClintock
45,783 PointsHowie,
The reason for the concatenation is that you are inserting variables into your property declaration. We need to break out of the string, then tell the code to concatenate a value, then concatenate back into the string, rinse and repeat until we've inserted all of our values. The + character is just how we happen to achieve this in JavaScript. To string together multiple things in one value, we concatenate!
Erik
Corbin Balzan
11,751 PointsAre the + characters breaking out of the string? I am confused on how you break out, then concatenate the value, then concatenate back into the string.
Erik McClintock
45,783 PointsCorbin,
The different pairs of quotation marks are what break you in and out of the string, and the plus signs concatenate those strings together with whatever you place in between. You are able to break in and out and concatenate as many things together into the string as you like before you place the closing semi-colon to end the statement.
Erik
Corbin Balzan
11,751 PointsErik,
Thank you for the help! I understood the concatenation and breaking out of the strings I was just wondering why the + sign would be on both sides of the variable. Now as I have taken a second look at the code I see why they are there. Thank you again for helping point it out to me!
Corbin
Nicholas Elliott
Full Stack JavaScript Techdegree Graduate 19,539 PointsNicholas Elliott
Full Stack JavaScript Techdegree Graduate 19,539 PointsInstead of viewing the code with the quotations around the 2 plus signs and the letter 'r' like this: " + r + "
View the quotations around the 'rgb' and paranthesis like this: "rgb("
With that in mind, realize that the strings:
"rgb("
","
", "
")"
are being concatenated with the variables:
r
g
b
to form: "rgb(" + r + "," + g +", " + b + ")"
Hope this helps because I had the same thought when first seeing our instructor type it out.