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var op = document.createElement("option"); op.value = i; op.innerHTML = i; oSelect.appendChild(op);
oSelect.options.add(new Option(i, i));
oSelect.options.length = iLength;
for (var i = 0; i < iLength; i++) { oSelect.options[i].text = oSelect.options[i].value = iStart + i; }
<select id="testSel"></select>
<div id="testShow"></div>
<input name="" type="button" value="效率测试" id="testBtn" />
<script>
document.getElementById("testBtn").onclick = function(){
var testSel = document.getElementById("testSel"), testShow = document.getElementById("testShow"), iMin = 0, iMax = 1000, dt;
testShow.innerHTML = "";
dt = new Date().getTime();
var len = iMax - iMin + 1; testSel.options.length = len;
for (var i = 0; i < len; i++) { testSel.options[i].text = testSel.options[i].value = iMin + i; }
testShow.innerHTML += "笨方法:" + (new Date().getTime() - dt) + " 毫秒;";
dt = new Date().getTime();
testSel.options.length = 0;
for (var i = iMin; i <= iMax; i++) { testSel.options.add(new Option(i, i)); }
testShow.innerHTML += "new Option方法:" + (new Date().getTime() - dt) + " 毫秒;";
dt = new Date().getTime();
testSel.options.length = 0;
for (var i = iMin; i <= iMax; i++) { var op = document.createElement("option"); op.value = i; op.innerHTML = i; testSel.appendChild(op); }
testShow.innerHTML += "dom方法:" + (new Date().getTime() - dt) + " 毫秒;";
}
</script>
oSelect.selectedIndex = iIndex;
<select id="idSelected"></select>
<input name="" type="button" value="默认项测试" id="testBtnSelected" />
<script>
document.getElementById("testBtnSelected").onclick = function(){
var oSelect = document.getElementById("idSelected");
oSelect.options.length = 0;
for (var i = 0; i <= 10; i++) {
var op = document.createElement("option"); op.value = op.innerHTML = i; oSelect.appendChild(op);
}
oSelect.selectedIndex = 5;
}
</script>
if(i == 4){ op.selected = true; }
setTimeout(function(){ oSelect.selectedIndex = iIndex; }, 0);
oSelect.options[iIndex].setAttribute("selected", "true");