虽然鼠标按下 JS

Question

I'm trying to run a function while mousedown but for the life of me I can't get it to work while holding down but everything works by just clicking. I'm trying to change color of countries on a map as I hold down. Here's my code:

    var int;
    var mouseStillDown = false;

      function mousedown(geography) 
      {     console.log('mousedown '+mousedownID);
             mouseStillDown = true;
          int = setInterval( performWhileMouseDown(geography), 100);
      }



    function mouseup() 
    {
        clearInterval(int);  
        mouseStillDown = false;
    }

     function mouseout() 
    {
        clearInterval(int);  
    }

      function performWhileMouseDown(geography)
       {
             if (!mouseStillDown)
              {console.log('error');}

            if (mouseStillDown) {
           if(data[geography.id])
            {
              data[geography.id] ++;
            }else
              {
                data[geography.id] = 1;
              }
            var m = {};                                        
            m[geography.id] = color(data[geography.id]);
            map.updateChoropleth(m);
              }

            /* if (mouseStillDown)
              { setInterval(performWhileMouseDown(geography), 100); }*/
      }

Answer 1

You could try to use mousemove instead, mousedown will only fire once.

var mouseDown = false;
window.addEventListener('mousedown', function() { mouseDown = true })
window.addEventListener('mouseup', function() { mouseDown = false })
window.addEventListener('mousemove', function() { 
  if (!mouseDown) {
    return;
  }
  // perform while mouse is moving
})

Answer 2

here's what worked for me

 var timeout ;
function mouseDown(geography){

    timeout = setInterval( function(){


            if(data[geography.id]){

              data[geography.id] ++;
            }else{
              data[geography.id] = 1;
            }
            var m = {};                                        
            m[geography.id] = color(data[geography.id]);
            map.updateChoropleth(m);}, 100);

    return false;
}


function mouseUp(geography){

clearInterval(timeout);
    return false;
}