87,955
社区成员
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<select id="roots">
<option value=1>浙江</option>
<option value=2>山东</option>
<option value=3>江苏</option>
.......
</select>
<select id="sons">
<option value=1>杭州</option>
<option value=2>宁波</option>
.....
</select>
<select id="sons">
<option value=3>济南</option>
<option value=4>青岛</option>
.....
</select>
<select id="sons">
<option value=5>南京</option>
<option value=6>苏州</option>
.....
</select>
......
<select id="roots" value="">
<option value="0">...</option>
<option value=1>浙江</option>
<option value=2>山东</option>
<option value=3>江苏</option>
</select>
<select name="sons" style="display:none">
<option value=1>杭州</option>
<option value=2>宁波</option>
</select>
<select name="sons" style="display:none">
<option value=3>济南</option>
<option value=4>青岛</option>
</select>
<select name="sons" style="display:none">
<option value=5>南京</option>
<option value=6>苏州</option>
</select>
var roots = document.getElementById("roots");
var sons = document.getElementsByName("sons");
roots.onchange = function(){
console.log(typeof this.value == "string");
if(typeof this.value == "string" && this.value == "1"){
for(var i=0;i<sons.length;i++){
if(i == 0){
sons[i].setAttribute("style","display:block");
}else{
sons[i].setAttribute("style","display:none");
}
}
}else if(typeof this.value == "string" && this.value == "2"){
for(var i=0;i<sons.length;i++){
if(i == 1){
sons[i].setAttribute("style","display:block");
}else{
sons[i].setAttribute("style","display:none");
}
}
}else if(typeof this.value == "string" && this.value == "3"){
for(var i=0;i<sons.length;i++){
if(i == 2){
sons[i].setAttribute("style","display:block");
}else{
sons[i].setAttribute("style","display:none");
}
}
}else{
for(var i=0;i<sons.length;i++){
sons[i].setAttribute("style","display:none");
}
}
};