Question

When I try to pass a string to a function like so

i="file:///bla/bla/bla";
Fade(i);

i get Uncaught SyntaxError: Unexpected token :

so i tried passing a literal in the function like f("img1.jpg");
and i got

Uncaught ReferenceError: img1 is not defined
(anonymous function)

What is going on?

(note that i am kind of new in js)

In particular:

timeout = 3;
var fadetime = 5;
var curr = 0;

var fadedelta = 100/(fadetime*30);
var opac = 100;

//var fadedelta = 100/(fadetime*3);
//prelaod all images just to have them there
var namearr = new Array( "img1.jpg", "img2.jpg", "img3.jpg", "img4.jpg");
var imgarr = new Array();

var i = 0;
for( i = 0; i<2 ; i++)
{
    var tmp = new Image()
    tmp.src = namearr[i];
    imgarr.push(tmp); 
}

function setOpacity(image, op)
{
    if(typeof(image.filters) != 'undefined' )
    {
        image.filters.alpha.opacity = op;
    }
    else
    {
        image.style.opacity = op/100;
    }
}

function fadeIn(isrc)
{
    var locimg = document.getElementById("image");
    opac -=fadedelta;
    setOpacity(locimg,opac);
    if(opac>0)
    {
        setTimeout("fadeIn(String("+isrc+"));", 30);
    }
    else
    {
        locimg.src = isrc;
        setOpacity(locimg,100);
        opac=100;
    }
}


function Fade(isrc)
{
    var locimg = document.getElementById("image");
    var locdiv = document.getElementById("imageArea");

    locdiv.style.backgroundImage = "url("+isrc+")";
    fadeIn(isrc);
}

function aStatus()
{
    var locimg = document.getElementById("image");
    var locdiv = document.getElementById("imageArea");

    alert("background: "+locdiv.style.backgroundImage+"\nforeground: "+locimg.src+"\ncurr: "+curr);
}

function onClick()
{
    curr = curr + 1;
    curr%=imgarr.length;
    Fade(String(""+imgarr[curr].src));
}

and the output is the Uncaught SyntaxError: Unexpected token : error refering to the line before the last (Fade(String(imgarr[curr].src));)

note that imgarr[curr].src is file:///home/fakedrake/webdev/img1.jpg or file:///home/fakedrake/webdev/img2.jpg depending on the value of curr

Answer 1

I got a totally different error, about a “missing ) after argument list” on line

fadeIn(file:///some/local/file.jpg);

However, the problem is the same: the interpreter thinks that fadeIn gets a variable name (in this case file:///some/local/file.jpg, which is not a valid identifier) instead of a string.

The solution is simple: add single quotes to

setTimeout("fadeIn('"+isrc+"')", 30);
    // here        ^        ^