Default parameters in javascript functions

[vediam]

Is it possible to have default parameters in javascript functions like you can in other laguages such as PHP? I would like to do something like this:

function setTagHoverColor( tagType, className, color = "#FFFF00" )
{
}

[SimplyFu]

unfortunately, no such capability in this point of time, but you can always do this

function setTagHoverColor( tagType, className, color )
{
if (color == undefined) {
color = "#FFFF00";
}
}

[Pepejeria]

The if is not needed:

function setTagHoverColor(tagType, className, color) {
    color = color || "#ff0";
}

[stereofrog]

The latter won't work if 0 is an allowed parameter value. "Undefined" check looks cleaner, though more verbose.

[Pepejeria]

True, though color expects a String. You would basically need check to check that as well if you wanna be bulletproof. Somebody might pass a function, null, object etc...

[siteguru]

I wonder what is driving this question? I thought I had seen the exact same question before, quite recently.

http://www.sitepoint.com/forums/show...54#post3347854

[Pepejeria]

Ah right, and I replied to that one as well. I am apparently senile.

[siteguru]

Different guy asking the question this time though.

Which begs the question - does nobody bother with the search function anymore?

[SimplyFu]

furthermore if we have functions that may contain unlimited parameters for example

function x(a,b,c*) {

}
x(1,2,3) // call with parameter 1,2,3
x(1,2,3,4) // call with parameter 1,2,3,4

this will need to deal with special variable call argument and special method call apply. Haven't really explore deeply into it yet.