Hey there, let's break down and fix the issues you're facing step by step:

1. Resolve the "Uncaught ReferenceError: $row is not defined" #

The error pops up because you're assigning to $row without declaring it first (using let, const, or var). Plus, child is a raw DOM element—you need to wrap it in a jQuery object ($(child)) to use your custom .flash() method, since that method is added to jQuery's prototype.

Replace this line:

$row = child;

With:

let $row = $(child);

2. Ensure jQuery Can Animate Background Colors #

By default, jQuery's .animate() method doesn't support animating color properties like backgroundColor. To get that smooth flash transition working, you'll need to include either:

• The jQuery Color plugin (a lightweight tool focused solely on color animations)
• Or the full jQuery UI library (which includes color animation support alongside other UI features)

Without one of these, the background color will jump abruptly instead of fading in/out.

Corrected Full Code #

Here's your updated table update function with all fixes applied:

var child = createStockNode(stock, type, template); 
// Try to replace existing stock node
var stockNode = document.querySelector(type + "[data-symbol=" + stock.n + "]");
if (stockNode) {
    table.replaceChild(child, stockNode);
} else {
    // Add new stock to table
    table.appendChild(child);
}

// Determine flash color based on price change (stock.c is close price)
var bg = stock.c < 0 ? '255,148,148' // Red for price drop
    : '154,240,117'; // Green for price rise

// Fix: Declare $row and wrap child in jQuery object
let $row = $(child);
$row.flash(bg, 1000);

Your existing .flash() method is solid once you fix the above issues, but here it is for reference:

jQuery.fn.flash = function (color, duration) {
    var current = this.css('backgroundColor');
    this.animate({ backgroundColor: 'rgb(' + color + ')' }, duration / 2)
        .animate({ backgroundColor: current }, duration / 2);
};

Quick Final Checks #

• Double-check that jQuery is loaded before your custom .flash() method and table update code
• Confirm you've added the jQuery Color or jQuery UI library if you want smooth color transitions
• Make sure createStockNode returns a valid DOM element (like a <tr> row) that can have its background color animated

内容的提问来源于stack exchange，提问作者theo