How do I get the td color to change color upon a second click?

Question

Here is my code below. I am attempting to reverse the click that was already made. This is happening with a td tag. I have combined failed experiments from several questions here and other forums.

function changeColor(elem) {
    if (elem.style.backgroundColor = "#5AD9C1" || "transparent") {
        elem.style.backgroundColor = "#66FF66";
    } else if (element.style.backgroundColor = "#66FF66") {
        elem.style.backgroundColor = "#5AD9C1";
    }
};

Answer 1

First:

// With '=' you do assign a value to backgroundColor
if (elem.style.backgroundColor = "#5AD9C1" ...)

// Use '==' to check, if a equals b
if(elem.style.backgroundColor == "#5AD9C1" ...)

Second:

You can't chain if-statements like this:

if(myVar == 'A' || 'B' || 'C')

It's the same as asking if('B') which is always true

You have to do it like this:

if(myVar == 'A' || myVar == 'B' || myVAR == 'C')

For detailed information about if-statements and operators see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/if...else

The correct solution is:

function changeColor(elem) {
    if (elem.style.backgroundColor == "#5AD9C1" || elem.style.backgroundColor == "transparent") {
        elem.style.backgroundColor = "#66FF66";
    } else if (element.style.backgroundColor == "#66FF66") {
        elem.style.backgroundColor = "#5AD9C1";
    }
}

edit:

As mentioned in the comments, the main reason why this does not work is because style.backgroundColor is returning the color as RGB value

I found this solution for converting rgb to hex.

Answer 2

You should use a class so that it can be maintained from a stylesheet.

.state2 {
   background-color: #66FF66;
}
.state1{
   background-color: #5AD9C1;
}

Possibly one of the states may be redundant and should be applied to the base element allowing you to toggle the class instead.

If you have jQuery available use the following:

if($element.hasClass('state1')) {
   $element.removeClass('state1').addClass('state2');
else{
   $element.removeClass('state2').addClass('state1');
}

The above can be improved quite a bit especially if there was some example HTML.

If you don't have the luxury of using jQuery you can look at alternatives or use some of these replacements: http://toddmotto.com/creating-jquery-style-functions-in-javascript-hasclass-addclass-removeclass-toggleclass/

EDIT: I have added an answer that solves your problem. Although I still don't recommend doing this: http://jsfiddle.net/po16f5ec/4/

I also referenced this article for the hex to rgb: RGB to Hex and Hex to RGB

Answer 3

Many browsers, certainly Chrome and Firefox (from experience) return their colors in rgb() format, rather than hexadecimal; regardless of the format in which they were supplied (#fff, white, hsl(0,100%,100%) all return rgb(255,255,255)).

That said, if you use css class-names then you don't need to worry about toggling between specific colours, or how to compensate for the vagaries in how specific browsers return those colours. In plain JavaScript, for example it's quite simple to implement a class-change function that achieves the same end-result:

function toggleClass(elem, cssClassOn) {
    var test = elem.classList.contains(cssClassOn);
    elem.classList[ test ? 'remove' : 'add' ](cssClassOn);
}

document.getElementById('test').addEventListener('click', function (e) {
    toggleClass(e.target, 'on');
});

JS Fiddle demo.

The above, of course, needs to be coupled with the appropriate CSS styling.

For those browsers that don't implement the Element.classList API, a simple alternative is:

function toggleClass(elem, cssClassOn) {
    var currentClasses = elem.className,
        test = currentClasses.indexOf(cssClassOn) > -1;

    if (test) {
        elem.className = currentClasses.replace(cssClassOn,'');
    }
    else {
        elem.className += currentClasses + ' ' + cssClassOn;
    }
}

JS Fiddle demo.

References:

• Element.classList.
• Element.className.
• EventTarget.addEventListener().

Answer 4

Be careful with = and ==

function changeColor(elem) {
  if (elem.style.backgroundColor == "#5AD9C1" || elem.style.backgroundColor == "transparent") {
    elem.style.backgroundColor = "#66FF66";
  } else if (element.style.backgroundColor == "#66FF66") {
    elem.style.backgroundColor = "#5AD9C1";
  }