小编Leo*_*tto的帖子

const e = document.getElementsByClassName('scan')[0];
document.onmousemove = function(event){
  e.style.left = `${event.clientX}px`;
};

*{
    margin: 0;
    padding: 0;
}

html, body{
    width: 100%;
    min-height: 100vh;
    overflow-x: hidden;
    
    display: flex;
}

.banner{
    width: 100vw;
    height: 100vh;

    display: flex;
    flex-grow: 1;
    flex-direction: row;
    align-items: center;
    background-color: #031321;
}

.banner .scan{
    width: 7px;
    height: 80%;
    
    position: absolute;
    left: 30px;
    z-index: 3;

    transition: left 50ms ease-out 0s;
    
    border-radius: 15px;
    background-color: #fff;
    box-shadow:
        0 0 15px 5px #fff,  /* inner white */
        0 0 35px 15px …

var draggingMouse = false;
var leftMouseDrag, topMouseDrag;
$(document).on("mousedown mouseup", "#cloud_main_page", function(e){	
	if (e.type == "mousedown") {
		draggingMouse = true;
		var offset = $(this).offset();
		
		leftMouseDrag = e.pageX - offset.left;
		topMouseDrag = e.pageY - offset.top
		
		$("#cloud_main_page .cloud_mouse_selection").css({"top": topMouseDrag, "left" : leftMouseDrag});
			
	} else{
		draggingMouse = false;	
		$("#cloud_main_page .cloud_mouse_selection").removeAttr("style");
	}
		
}).on("mousemove", "#cloud_main_page", function(e){
	if(draggingMouse){
		var offsetDrag = $("#cloud_main_page .cloud_mouse_selection").offset();
			
		var top = e.pageY - offsetDrag.top;
		var left = e.pageX - offsetDrag.left;
      
		var width = Math.abs(left);
		var height = Math.abs(top);
			
		$("#cloud_main_page .cloud_mouse_selection").css({"width": width, …