Event.eventPhase

表示事件物件目前於事件流（Event Flow）中傳遞的進度為哪一個階段。

語法

var phase = event.eventPhase;

回傳一個整數值以代表目前事件於事件流中的傳遞階段，可能的值將於事件傳遞階段常數說明。

常數

事件傳遞階段常數

These values describe which phase the event flow is currently being evaluated.

For more details, see section 3.1, Event dispatch and DOM event flow, of the DOM Level 3 Events specification.

範例

HTML Content

<h4>Event Propagation Chain</h4>
<ul>
  <li>Click 'd1'</li>
  <li>Analyse event propagation chain</li>
  <li>Click next div and repeat the experience</li>
  <li>Change Capturing mode</li>
  <li>Repeat the experience</li>
</ul>
<input type="checkbox" id="chCapture" /> 
<label for="chCapture">Use Capturing</label>
 <div id="d1">d1
  <div id="d2">d2
      <div id="d3">d3
          <div id="d4">d4</div>
      </div>
  </div>
 </div>
 <div id="divInfo"></div>  

CSS Content

div { 
  margin: 20px;
  padding: 4px;
  border: thin black solid;
} 

#divInfo { 
  margin: 18px;
  padding: 8px;
  background-color:white;
  font-size:80%; 
}

JavaScript Content

var clear = false, divInfo = null, divs = null, useCapture = false;
window.onload = function () {
  divInfo = document.getElementById("divInfo");
  divs = document.getElementsByTagName('div'); 
  chCapture = document.getElementById("chCapture");
  chCapture.onclick = function () { 
    RemoveListeners();
    AddListeners(); 
  }
  Clear();
  AddListeners();
}

function RemoveListeners() { 
  for (var i = 0; i < divs.length; i++) { 
    var d = divs[i]; 
    if (d.id != "divInfo") { 
      d.removeEventListener("click", OnDivClick, true);
      d.removeEventListener("click", OnDivClick, false);
    }
  }
}

function AddListeners() { 
  for (var i = 0; i < divs.length; i++) { 
    var d = divs[i];
    if (d.id != "divInfo") { 
      d.addEventListener("click", OnDivClick, false); 
      if (chCapture.checked) 
        d.addEventListener("click", OnDivClick, true);
      d.onmousemove = function () { clear = true; }; 
    }
  }
} 

function OnDivClick(e) {
  if (clear) {
    Clear(); clear = false;
  }
  if (e.eventPhase == 2)
    e.currentTarget.style.backgroundColor = 'red';
  var level = e.eventPhase == 0 ? "none" : e.eventPhase == 1 ? "capturing" : e.eventPhase == 2 ? "target" : e.eventPhase == 3 ? "bubbling" : "error";
  divInfo.innerHTML += e.currentTarget.id + "; eventPhase: " + level + "<br/>";
}

function Clear() { 
  for (var i = 0; i < divs.length; i++) { 
    if (divs[i].id != "divInfo")
      divs[i].style.backgroundColor = (i & 1) ? "#f6eedb" : "#cceeff";
  } 
  divInfo.innerHTML = ''; 
}

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