做联动下拉,利用js是下拉列表动态增长了,可每次换个母选项,子下拉列表就会接着上次的继续增加,js怎么做才能让选完母下拉时清空子下拉的option?
<script>
function loadCourse(ss){
var shouji = ss.value;
var url = "shouji.do?shouji="+shouji;
alert(url);
//Element.remove("option");
new Ajax.Request(url,{
method :"get",
onSuccess : function(resp){
alert(resp.responseText);
var rescive = resp.responseText;
var re = rescive.split(",");
var i = 1;
for(i=1;i<re.length-1;i++){
option = document.createElement("option");
option.text=re[i];
option.value=re[i];
Input.add(option);
}
}
});
} </script>
<script>
function loadCourse(ss){
var shouji = ss.value;
var url = "shouji.do?shouji="+shouji;
alert(url);
//Element.remove("option");
new Ajax.Request(url,{
method :"get",
onSuccess : function(resp){
alert(resp.responseText);
var rescive = resp.responseText;
var re = rescive.split(",");
var i = 1;
for(i=1;i<re.length-1;i++){
option = document.createElement("option");
option.text=re[i];
option.value=re[i];
Input.add(option);
}
}
});
} </script>
// 根据control1的值来动态设置control2的内容:
function changeTest(control1, control2) {
control2.options.length=0;
if(control1.value=="0"){
control2.options.add(new Option("滞留1",1));
control2.options.add(new Option("滞留2",2));
}else{
control2.options.add(new Option("----",0));
}
return;
}control2.options.length=0;
==》清空下拉列表,然后重新设置新的值。
var count = Input.options.length;
for(int i=count-1;i>=0;i--){
Input.options.remove(i);
}
for(i=1;i <re.length-1;i++){
option = document.createElement("option");
option.text=re[i];
option.value=re[i];
Input.options.add(option);
}