//根据值选中下拉菜单某项

function setSelectedValue(id,value){

var selectObj = document.getElementById(id);

for(i=0;i<selectObj.length;i++){

if(selectObj.options[i].value==value){

selectObj.options[i].selected = "selected";

}

}

}

//获取下拉菜单当前选择的值

function getSelectedValue(id){

var value = document.getElementById(id).value;

return value;

}

//根据值选择多个下拉选项

function setSelectedValues(id,values){

var selectObj = document.getElementById(id);

for(var i=0;i<values.length;i++){

value = values.split(",");

for(var j = 0;j<value.length;j++){

for(var k = 0;k<selectObj.length;k++){

if(selectObj.options[k].value==value[j]){

selectObj.options[k].selected = "selected";

}

}

}

}

}

//获取下拉菜单当前选中的多个值

function getSelectedValues(id){

var selectObj = document.getElementById(id);

var values = "";

for(var i = 0;i<selectObj.length;i++){

if(selectObj.options[i].selected){

var value1 = selectObj.options[i].value;

var value = value1 + ",";

va