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  <title>ondragleave — counter pattern</title>

  <style>body{font-family:system-ui,sans-serif;margin:0;padding:1.5rem;background:#f8fafc;color:#334155;line-height:1.7}h1{margin:0 0 .75rem;font-size:1.25rem;color:#0f172a}.drag-box{display:inline-block;padding:1rem 1.25rem;border:2px dashed #cbd5e1;border-radius:8px;background:#fff;cursor:grab;user-select:none;max-width:420px}.drag-box:active{cursor:grabbing}.drop-zone{margin-top:1rem;padding:1.25rem;border:2px dashed #94a3b8;border-radius:8px;background:#f1f5f9;max-width:420px;min-height:3rem;transition:background .15s,border-color .15s}.drop-zone.over{border-color:#3b82f6;background:#eff6ff}.inner{margin-top:.75rem;padding:.75rem 1rem;border:2px dashed #cbd5e1;border-radius:6px;background:#fff;font-size:.875rem}.status{margin-top:1rem;padding:.75rem 1rem;background:#f0fdf4;border:1px solid #bbf7d0;border-radius:8px;font-size:.8125rem;max-width:420px}.count{font-weight:600;color:#15803d}</style>

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  <h1>Enter/leave counter pattern</h1>

  <p>Drag over the nested inner box. Without a counter, dragleave on the parent would flicker the highlight.</p>

  <div class=drag-box draggable=true>Drag me into the nested zone.</div>

  <div class=drop-zone id=zone>

    Outer drop zone

    <div class=inner>Nested child (still inside zone)</div>

  </div>

  <div class=status>Enter count: <span class=count id=count>0</span></div>

  <div class=status id=msg>Unhighlight only when count reaches 0.</div>



  <script>var zone=document.getElementById("zone"),countEl=document.getElementById("count"),msg=document.getElementById("msg"),enterCount=0;zone.addEventListener("dragenter",(function(){enterCount+=1,countEl.textContent=String(enterCount),zone.classList.add("over"),msg.textContent="dragenter — count is "+enterCount+"."})),zone.addEventListener("dragleave",(function(){enterCount-=1,countEl.textContent=String(enterCount),0===enterCount?(zone.classList.remove("over"),msg.textContent="dragleave — count reached 0, highlight removed."):msg.textContent="dragleave — count is "+enterCount+" (still inside zone)."})),zone.addEventListener("dragover",(function(e){e.preventDefault()})),zone.addEventListener("drop",(function(e){e.preventDefault(),enterCount=0,countEl.textContent="0",zone.classList.remove("over"),msg.textContent="drop — counter reset."}))</script>

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HTML ondragleave Attribute — Enter/Leave Counter Pattern
