<input type="text" name="a" >
<select name="">
<option value="1">请选择</option>
<option value="2">1</option>
<option value="3">1</option>
<option value="4">1</option>
</select>
<input type="submit" value="submit" onclick="return check()"><script>
function check(){
if(document.getElementById("a").indexOf("中国") != -1){
if(document.getElementsByName("b")[0].selected == true){
alert("please select!");
return false;
}
}
}
}
</script>
<select name="">
<option value="1">请选择</option>
<option value="2">1</option>
<option value="3">1</option>
<option value="4">1</option>
</select>
<input type="submit" value="submit" onclick="return check()"><script>
function check(){
if(document.getElementById("a").indexOf("中国") != -1){
if(document.getElementsByName("b")[0].selected == true){
alert("please select!");
return false;
}
}
}
}
</script>
<option value="1">请选择</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
</select>
<input type=button value=test onclick="var the = document.getElementById('aa').options[2]; the.value='22';the.text='22'">
<select name="b">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
<input type="submit" value="submit" onclick="return check()"><script>
function check(){
if(document.getElementById("a").indexOf("中国") != -1){
if(document.getElementsByName("b")[0].selectedIndex == -1){
return false;
}
}
return true;
}
</script>
这行一直提示错误:缺少对象
楼主幸运地选了最差答案<input type="text" name="a" id="a"><!--建议最好加上id="a"-->
<select name="b"><!--错误-->
<option value="1">请选择</option>
<option value="2">1</option>
<option value="3">1</option>
<option value="4">1</option>
</select>
<input type="submit" value="submit" onclick="return check()"><script>
function check(){
if(document.getElementById("a").value.indexOf("中国")>=0){//缺少.value
if(document.getElementsByName("b")[0].selectedIndex == 0){//乱搞
alert("please select!");
return false;
}
}
else//不能很好理解“反之不能选”
document.getElementsByName("b")[0].selectedIndex = 0;
}
//多了一个}
</script>