Javascript无法设置颜色

Question

The function is called via:

myChart.gChangeBarColour(1, "#000000");

This works:

   // Changes bars colour
    this.gChangeBarColour = function(gBarID, gBarColour) {

        if (gBarID <= this.gData.length && gBarID >= 0) {

            document.getElementById("gBar" + gBarID).style.backgroundColor = '#000000';

        }

    }

But this doesn't work:

// Changes bars colour
this.gChangeBarColour = function(gBarID, gBarColour) {

    if (gBarID <= this.gData.length && gBarID >= 0) {

        document.getElementById("gBar" + gBarID).style.backgroundColor = '" + gBarColour + "';

    }

}

No errors in the console at all! Any ideas?

Answer 1

Your '" + gBarColour + "' is a string , delimited by single quotes ' that contains " + gBarColour + " , that value is then used as the color.

You need to leave out all the quotes and plus signs:

// assign the value of gBarColour to the backgroundColor property
document.getElementById("gBar" + gBarID).style.backgroundColor = gBarColour;

Answer 2

'" + gBarColour + "'

should be

gBarColour or ''+gBarColour