一个用javascript写的select支持上下键、首字母筛选以及回车取值的功能_javascript技巧

 调用时可以这样：

1，tempStr=GetNewSelectStr(dataTable.value,"select"+rowIndex,true);
2,makeSelectBox("select"+rowIndex,tempStr,value,obj);

tempStr－这个是返回的下拉列表值的框体
dataTable.value－这个是数据源（我这里是一张表）
"select"+rowIndex－这个是ID号，也就是当前这个select的id号（我这里是有多个select所以ID号是自动的）
true－这个是控制单击时出现下拉框体的标识
value－这个是初始的时候显示在select输入框中的值
obj－这个是要显示select的对象

源代码：

var tempStr=GetNewSelectStr(dataTable.value,"select"+rowIndex,true);
makeSelectBox("select"+rowIndex,tempStr,value,obj);
var nowOpenedSelectBox = "";
var mousePosition = "";
var userList=null;
function selectThisValue(thisId,thisIndex,thisValue,thisString) {
var objId = thisId;
var nowIndex = thisIndex;
var valueString = thisString;
var sourceObj = $(objId);
var nowSelectedValue = document.getElementById(nowIndex+thisId).innerHTML;
hideOptionLayer(objId);
if (sourceObj) sourceObj.value = nowSelectedValue;
settingValue(objId,valueString);
selectBoxFocus(objId);
if (sourceObj.onchange) sourceObj.onchange();
}

function settingValue(thisId,thisString) {
var objId = thisId;
var valueString = thisString;
var selectedArea = document.getElementById(objId+"selectBoxSelectedValue");
if (selectedArea) {
if(navigator.appName.indexOf("Explorer") > -1){
selectedArea.innerText = valueString;
}
else{
selectedArea.textContent = valueString;
}
}
}

var l=0;
//显示下拉框中的值
function viewOptionLayer(thisId,Istask,flag) {
var objId = thisId;
var selectInfo="";
var optionHeight = 18; // 高
var optionMaxNum = 7; //
var optionInnerLayerHeight = "";
var selectBoxWidth =130;
var selectBoxHeight =17;
l=userList.Rows.length;
var optionLayer = document.getElementById(objId+"selectBoxs");
if(optionLayer.innerHTML=="")
{
if (l > optionMaxNum) optionInnerLayerHeight = "height:"+ (optionHeight * optionMaxNum) + "px";
selectInfo = "

";
if(Istask=="true")
{
selectInfo += " ";
selectInfo += " ";
selectInfo += " ";
selectInfo += " ";
selectInfo += " ";
selectInfo += " ";
}
else
{
selectInfo += " ";
selectInfo += " ";
selectInfo += " ";
}
selectInfo += " ";
selectInfo += " ";
selectInfo += " ";
selectInfo += "

"; selectInfo += " "; selectInfo += " "; for (var i=0 ; i < l ; i++) { var nowValue = userList.Rows[i][userList.Columns[0].Name]; var nowText = userList.Rows[i][userList.Columns[0].Name]; if(Istask=="true") { selectInfo += " "; } else { selectInfo += " "; } selectInfo += " "; // selectInfo += " "; selectInfo += " "; } selectInfo += " " + nowText + " "; selectInfo += " "; selectInfo += "

";
optionLayer.innerHTML=selectInfo;
}
if (flag && optionLayer.style.display=="none"){ optionLayer.style.display = "";optionLayer.focus();}
else
{
optionLayer.style.display = "none";
if(document.getElementById("level"))
{
document.getElementById("level").style.display="";
}
if(document.getElementById("priority"))
{
document.getElementById("priority").style.display="";
}
}
if(!flag){optionLayer.style.display = "";optionLayer.focus();}
for(var i=0;i{
if(document.getElementById("select"+i+""+"viewOptions"))
{
document.getElementById("select"+i+""+"viewOptions").style.display="none";
}
}
document.getElementById(objId+"viewOptions").style.display="";
if(document.getElementById("level"))
{
document.getElementById("level").style.display="none";
}
if(document.getElementById("priority"))
{
document.getElementById("priority").style.display="none";
}
nowOpenedSelectBox = objId;
setMousePosition("inBox");
}
//支持首字母筛选、回车键取值、上下键选值功能
function firstLetter(thisId){
var count=0;
var selectedVal="";
if(document.getElementById(thisId+"viewOptions").style.display=="")
{
document.getElementById(thisId+"viewOptions").focus();
var asciiCode=String.fromCharCode(event.keyCode).toLowerCase();
var selectValue="";
if(event.keyCode==38)
{
for(var i=0;i{
if(document.getElementById(i+thisId).className=="selectBoxOptionOver" && i>0)
{
document.getElementById(i+thisId).style.backgroundColor='#ffffff';
document.getElementById(i+thisId).style.color='#253449';
document.getElementById(i+thisId).className='selectBoxOption';
document.getElementById((i-1)+thisId).style.backgroundColor='#2c59aa';
document.getElementById((i-1)+thisId).style.color='#ffffff';
document.getElementById((i-1)+thisId).className='selectBoxOptionOver';
document.getElementById(thisId+"viewOptions").scrollTop= (i-1)*20;
count=1;
break;
}
}
if(count==0)
{
document.getElementById((l-1)+thisId).style.backgroundColor='#2c59aa';
document.getElementById((l-1)+thisId).style.color='#ffffff';
document.getElementById((l-1)+thisId).className='selectBoxOptionOver';
}
}
if(event.keyCode==40)
{
for(var i=0;i{
if(document.getElementById(i+thisId).className=="selectBoxOptionOver" && i{
document.getElementById(i+thisId).style.backgroundColor='#ffffff';
document.getElementById(i+thisId).style.color='#253449';
document.getElementById(i+thisId).className='selectBoxOption';
document.getElementById((i+1)+thisId).style.backgroundColor='#2c59aa';
document.getElementById((i+1)+thisId).style.color='#ffffff';
document.getElementById((i+1)+thisId).className='selectBoxOptionOver';
if(i>10)
{
document.getElementById(thisId+"viewOptions").scrollTop= (i+1)*19;
}
else
{
document.getElementById(thisId+"viewOptions").scrollTop= (i+1)*10;
}
count=1;
break;
}
}
if(count==0)
{
document.getElementById(0+thisId).style.backgroundColor='#2c59aa';
document.getElementById(0+thisId).style.color='#ffffff';
document.getElementById(0+thisId).className='selectBoxOptionOver';
}
}
if(event.keyCode==13)
{
for(var i=0;i{
if(document.getElementById(i+thisId).className=="selectBoxOptionOver")
{
selectedVal=document.getElementById(i+thisId).innerHTML;
var sourceObj = $(thisId);
hideOptionLayer(thisId);
if (sourceObj) sourceObj.value = selectedVal;
settingValue(thisId,selectedVal);
selectBoxFocus(thisId);
if (sourceObj.onchange) sourceObj.onchange();
document.getElementById(thisId+"viewOptions").style.display="none";
if(document.getElementById("level"))
{
document.getElementById("level").style.display="";
}
if(document.getElementById("priority"))
{
document.getElementById("priority").style.display="";
}
break;
}
}
}
for(var i=0 ; i < l ; i++)
{
selectValue=document.getElementById(i+thisId).innerHTML;
if(asciiCode==selectValue.substring(0,1))
{
resetStyle(thisId);
document.getElementById(i+thisId).style.backgroundColor='#2c59aa';
document.getElementById(i+thisId).style.color='#ffffff';
document.getElementById(i+thisId).className='selectBoxOptionOver';
document.getElementById(thisId+"viewOptions").scrollTop= i*19;
break;
}
}
}
}
//清除被选中的下拉列表值的样式
function resetStyle(thisId){
for(var i=0;i{
document.getElementById(i+thisId).style.backgroundColor='#ffffff';
document.getElementById(i+thisId).style.color='#253449';
document.getElementById(i+thisId).className='selectBoxOption';
}
}
//隐藏下拉框
function hideOptionLayer(thisId) {
var objId = thisId;
var optionLayer = document.getElementById(objId+"selectBoxs");
if (optionLayer) optionLayer.style.display = "none";
if(document.getElementById("level"))
{
document.getElementById("level").style.display="";
}
if(document.getElementById("priority"))
{
document.getElementById("priority").style.display="";
}
}

function setMousePosition(thisValue) {
var positionValue = thisValue;
mousePosition = positionValue;
}

function clickMouse() {
if (mousePosition == "out") hideOptionLayer(nowOpenedSelectBox);
}

function selectBoxFocus(thisId) {
var objId = thisId;
var obj = document.getElementById(objId + "selectBoxSelectedValue");
obj.className = "selectBoxSelectedAreaFocus";
obj.focus();
}

function selectBoxBlur(thisId) {
var objId = thisId;
var obj = document.getElementById(objId + "selectBoxSelectedValue");
obj.className = "selectBoxSelectedArea";
}

function hiddenOptions(thisId){
document.getElementById(thisId+"viewOptions").style.display="none";
if(document.getElementById("level"))
{
document.getElementById("level").style.display="";
}
if(document.getElementById("priority"))
{
document.getElementById("priority").style.display="";
}
}

function makeSelectBox(index,newSelect,value,obj) {
newSelect=newSelect.replace(/(select0)/g,index);
$(obj).html(newSelect);
settingValue(index,value);
}
function GetNewSelectStr(table,index,IsTask){
userList=table;
var downArrowSrc = "../images/sanjiao.gif"; //三角
var downArrowSrcWidth = 16; //宽
var selectBoxWidth =130;
var selectBoxHeight =17;

newSelect=""
newSelect += "

";
newSelect += " ";
newSelect += " ";
newSelect += " ";
newSelect += "

"; newSelect += " "; if(IsTask) { newSelect += " "; newSelect += " "; } else { newSelect += " "; newSelect += " "; } newSelect += " "; newSelect += " "; newSelect += " "; newSelect += "

";
return newSelect ;
}