Javascript - Radio Button onChange
Question
Here is my code:
<html>
<head>
<script type="text/javascript">
function Change(radio)
{
if(radio.value)
{
setvalue = "Yes";
radiovalue = radio.value;
value = setvalue;
ChangeValue(radiovalue,value)
}
}
function ChangeValue(radiovalue, value)
{
alert(radiovalue+"=>"+value);
}
</script>
</head>
<body>
<?php
for($i = 1; $i <= 3; $i++)
{
?>
<input type="radio" name="choice" value="<?php echo $i;?>" onchange="Change(this);" /><br />
<?php
}
?>
</body>
</html>
There are 3 radio buttons in the web page.
From the above code, when I click the first radio button, it will show alert message for the radio button that I choosen (ie 1 => Yes).
Yes means that I choose the radio button.
No means that I didn't choose the radio button.
Now my questions is if I choose the first radio button, it will show alert message for each radio button
(ie 1 => Yes, 2 => No, 3 => No).
How should I modify?
3 answers
solution1
0 2014-09-13 03:11:19
In your example, radio.value will be the string "1" , "2" , or "3" . All of these are truthy, so the if block will always run. You need to compare the actual value using a comparison opperator such as == in your if statement.
Example:
if(radio.value == "1")
solution2
0 2014-09-13 03:34:10
I cut and pasted your example into a web app and it worked just the way you'd expect - both IE and chrome - so don't know why you're getting strange results. The if(radio.value) simply checks for the existence of a value (javascript thing) and is coded correctly. You might try onchange="return Change(this)" as some browsers may not like the open call.
solution3
0 2014-09-13 05:46:41
Plese try this
<html>
<head>
<script type="text/javascript">
function Change(radio) {
for (var i = 1; i < 4; i++) {
var ele = document.getElementById("choice_"+i);
if(ele.checked) {
setvalue = "Yes";
radiovalue = ele.value;
value = setvalue;
ChangeValue(radiovalue,value)
} else {
setvalue = "No";
radiovalue = ele.value;
value = setvalue;
ChangeValue(radiovalue,value)
}
}
}
function ChangeValue(radiovalue, value) {
alert(radiovalue+"=>"+value);
}
</script>
</head>
<body>
<?php
for($i = 1; $i <= 3; $i++) {
?>
<input type="radio" name="choice" id="choice_<?php echo $i;?>" value="<?php echo $i;?>" onchange="Change(this);" /><br />
<?php
}
?>
</body>
</html>
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.