if(zs=='0'){ document.getElementById("xs").options[0] = new Option("正整数","1"); document.getElementById("xs").options[1] = new Option("负整数","2"); }else{ document.getElementById("xs").options[0] = new Option("正小数","3"); document.getElementById("xs").options[1] = new Option("负小数","4"); }} function demo1(){ var xs = document.getElementById("xs").value; if(xs=='1'){ document.getElementById("sz").options[0] = new Option("1","1"); document.getElementById("sz").options[1] = new Option("2","2"); document.getElementById("sz").options[2] = new Option("3","3"); document.getElementById("sz").options[3] = new Option("4","4"); } if(xs=='2'){ document.getElementById("sz").options[0] = new Option("-1","-1"); document.getElementById("sz").options[1] = new Option("-2","-2"); document.getElementById("sz").options[2] = new Option("-3","-3"); document.getElementById("sz").options[3] = new Option("-4","-4"); } if(xs=='3'){ document.getElementById("sz").options[0] = new Option("0.1","0.1"); document.getElementById("sz").options[1] = new Option("0.2","0.2"); document.getElementById("sz").options[2] = new Option("0.3","0.3"); document.getElementById("sz").options[3] = new Option("0.4","0.4"); } if(xs=='4'){ document.getElementById("sz").options[0] = new Option("-0.1","-0.1"); document.getElementById("sz").options[1] = new Option("-0.2","-0.2"); document.getElementById("sz").options[2] = new Option("-0.3","-0.3"); document.getElementById("sz").options[3] = new Option("-0.4","-0.4"); } } </script>第一个下拉列表框从数据库里取出所有的值,选中其中一个,第二个下拉列表出现相对应的值,再选中其中一个,第三个下拉列表出现相对应的值? 我写了个简单的DEMO,给你点提示,对你来说,该循环的循环~ 2楼的朋友说的很正确,你最好是用AJAX来做,因为你每操作1次都是整体页面刷新,相应速度相对要慢~只要会JS,那么AJAX就不会太难~有时间到网上找一下AJAX的资料,很容易上手的!
<html>
<body>
<select name="zs" onchange="demo()">
<option value="">
==请选择==
</option>
<option value="0">
整数
</option>
<option value="1">
小数
</option>
</select>
<select name="xs" onchange="demo1()">
<option value="">
==请选择==
</option>
</select>
<select name="sz">
<option value="">
==请选择==
</option>
</select>
</body>
</html><script language="javascript">
function demo(){
var zs = document.getElementById("zs").value;
if(zs=='0'){
document.getElementById("xs").options[0] = new Option("正整数","1");
document.getElementById("xs").options[1] = new Option("负整数","2"); }else{
document.getElementById("xs").options[0] = new Option("正小数","3");
document.getElementById("xs").options[1] = new Option("负小数","4");
}}
function demo1(){
var xs = document.getElementById("xs").value;
if(xs=='1'){
document.getElementById("sz").options[0] = new Option("1","1");
document.getElementById("sz").options[1] = new Option("2","2");
document.getElementById("sz").options[2] = new Option("3","3");
document.getElementById("sz").options[3] = new Option("4","4");
}
if(xs=='2'){
document.getElementById("sz").options[0] = new Option("-1","-1");
document.getElementById("sz").options[1] = new Option("-2","-2");
document.getElementById("sz").options[2] = new Option("-3","-3");
document.getElementById("sz").options[3] = new Option("-4","-4");
}
if(xs=='3'){
document.getElementById("sz").options[0] = new Option("0.1","0.1");
document.getElementById("sz").options[1] = new Option("0.2","0.2");
document.getElementById("sz").options[2] = new Option("0.3","0.3");
document.getElementById("sz").options[3] = new Option("0.4","0.4");
}
if(xs=='4'){
document.getElementById("sz").options[0] = new Option("-0.1","-0.1");
document.getElementById("sz").options[1] = new Option("-0.2","-0.2");
document.getElementById("sz").options[2] = new Option("-0.3","-0.3");
document.getElementById("sz").options[3] = new Option("-0.4","-0.4");
}
}
</script>第一个下拉列表框从数据库里取出所有的值,选中其中一个,第二个下拉列表出现相对应的值,再选中其中一个,第三个下拉列表出现相对应的值?
我写了个简单的DEMO,给你点提示,对你来说,该循环的循环~
2楼的朋友说的很正确,你最好是用AJAX来做,因为你每操作1次都是整体页面刷新,相应速度相对要慢~只要会JS,那么AJAX就不会太难~有时间到网上找一下AJAX的资料,很容易上手的!
前几天刚做了 一个 四级连动 的 下拉菜单