Add field description property dynamically to the dialog through JS

I have a JS file for my validation of colorfield. In the process of validation, if any inaccessible color is added to the colorfield, then i want to add the field description with a msg for the user. 

i have a granite:data node as a child node to the colorfield. The granide:data node is having selector : contain. I am also able to successfully fetch and validate the color values that are getting selected in the swatch. I am also able to show the coral alert. But the problem is that it keeps coming one after the other. How can that fade away? or how can hi have only a single alert?

Below is my JS code:

$(window).adaptTo("foundation-registry").register("foundation.validation.validator", {
selector: "[data-contain]",
validate: function(el) {
var input = el.value;

var id = $(".cq-dialog").find("#colorId")[0]; //added ID to my colorfield, in case this can be used to get field description
if (input !== "#000000") //checking for inaccessible colors
{
var alert = new Coral.Alert();
alert.variant = "error";
alert.id="erroralert";
alert.header.textContent = Granite.I18n.get("ERROR");
alert.content.innerHTML = Granite.I18n.get("Failed to load log content.");
$("#colorId").append(alert);
}
});