content.js

// State of margins for toggling changes
var cozy_settings = {
    defaultMarginLeft: "",
    defaultMarginLeft: "",
    margin_state: 0,
};



function setMarginPercent(leftMarginInt, rightMarginInt) {
    document.body.style.marginLeft = leftMarginInt + "%";
    document.body.style.marginRight = rightMarginInt + "%";
}


// Icon click listener: adds 25% margins
chrome.runtime.onMessage.addListener(
    function(request, sender, sendResponse) {
        if (request.backgroundClick == true) {
            // margin option 0: default
            // margin option 1: 25%
            // margin option 2: 35%
            if (cozy_settings.margin_state == 0) {
                // If default, set left/right margins to 25%
                cozy_settings.defaultMarginLeft = (document.body.style !== null) ? document.body.style.marginLeft : "";
                cozy_settings.defaultMarginLeft = (document.body.style !== null) ? document.body.style.marginRight : "";
                setMarginPercent(25, 25);
                cozy_settings.margin_state = 1;
            } else if (cozy_settings.margin_state == 1) {
                // If default, set left/right margins to 35%
                setMarginPercent(35, 35);
                cozy_settings.margin_state = 2;
            } else {
                // Set margins to default
                document.body.style.marginLeft = cozy_settings.defaultMarginLeft;
                document.body.style.marginRight = cozy_settings.defaultMarginLeft;
                cozy_settings.margin_state = 0;
            }

            sendResponse(
                {result: "content.js processed backgroundClick == true"}
            );
            // Send response asynchronously
            return true; 
        }
});