select元素操作

//获得select元素当前选中的值
//输入参数：select表单元素
//返回：字符串
//get the value from select that selected


function getSelectValue(selobj)
{
	if (selobj.options.length == 0 || selobj.selectedIndex == -1) return null;
	var str;
	str = selobj.options[selobj.selectedIndex].value;
	return str;
}
//获得select元素当前选中的文本
//输入参数：select表单元素
//返回：字符串
//get the text from select that selected


function getSelectText(selobj)
{
	if (selobj.options.length == 0 || selobj.selectedIndex == -1) return null;
	var str;
	str = selobj.options[selobj.selectedIndex].text;
	return str;
}

function getSelectValueArray(selobj)
{
	var selNums = 0;
	for (var i = 0; i < selobj.options.length; i++)
	if (selobj.options[i].selected) selNums++;
	var options = new Array(selNums);
	var n = 0;
	for (var i = 0; i < selobj.options.length; i++)
	if (selobj.options[i].selected) options[n++] = selobj.options[i].value;
	return options;
}
//选中select指定选项，如果不存在不做处理


function selectedOne(selobj, value)
{
	var len = selobj.options.length;
	if (len == 0) return false;
	for (i = 0; i < len; i++)
	{
		if (selobj.options[i].value == value) selobj.options[i].selected = true;
	}
	return true;
}