Single-choice events in the HTML-CSS Group"

Because of a single choice button problem of death, N people come out, alas, even this cainiao-level character also came out, mixed water to fish. One accidentally touched one.

First, let's look at a piece of code that has been dug out from baidu.Copy codeThe Code is as follows: <script>
Function checkradio ()
{
For (I = 0; I <document. form1.Fruit. length; I ++)
{
If (document. form1.Fruit [I]. checked)
{
Alert ("your favorite fruit is:" + document. form1.Fruit [I]. nextSibling. nodeValue );
}
}
}
</Script>
<Form name = "form1">
Your favorite fruit is: <br>
<Input type = radio value = "Fruit1" name = "Fruit" checked> Apple
<Input type = radio value = "Fruit2" name = "Fruit"> banana
<Input type = radio value = "Fruit3" name = "Fruit"> strawberry
<Input type = radio value = "Fruit4" name = "Fruit"> pineapple
<Input type = button value = "select" onclick = "checkradio ()">
</Form>

This code is used to determine the selected value.

The result is that if every option is empty, a prompt should be given. The following code is the result after the change.

Program code
<Script>
Function checkradio ()
{
Var j = 0;
For (I = 0; I <document. form1.Fruit. length; I ++)
{
If (document. form1.Fruit [I]. checked = true)
{
Alert ("you have selected" + document. form1.Fruit [I]. nextSibling. nodeValue );
// Break; this break is not valid because it has been instructed by Feifei. Remove it.
} Else {
J = j + 1;
If (j = 4 ){
Alert! ");
}
}
}
}
</Script>
<Form name = "form1">
Your favorite fruit is: <br>
<Input type = radio value = "Fruit1" name = "Fruit">
Apple
<Input type = radio value = "Fruit2" name = "Fruit"> banana
<Input type = radio value = "Fruit3" name = "Fruit"> strawberry
<Input type = radio value = "Fruit4" name = "Fruit"> pineapple
<Input type = button value = "select" onclick = "checkradio ()">
</Form>

Later I saw a clearer piece of code written in the morning. I will post it here.
(Note: To facilitate the test, I changed the idea)Copy codeThe Code is as follows: <script>
Function checkradio ()
{
Var flag = false;
For (var I = 0; I <= document. form1.Fruit. length-1; I ++)
{
If (form1.Fruit [I]. checked ){
Flag = true ;}
}
If (flag)
{
Alert ("^_^ ");
Return false;
} Else {
Alert ("hero, you should choose one! ");
}
}
</Script>

The single choice is over, and Feifei's boss is not dead-hearted. At night, a code for the check box is developed.Copy codeThe Code is as follows: <script>
Var j = document. getElementsByName ("Fruit ");
Function allche (){
For (var I = 0; I <j. length; I ++ ){
If (document. form1.Fruit [I]. checked! = True) document. form1.Fruit [I]. checked = document. form1.suoy. checked;
If (document. form1.Fruit [I]. checked = true) document. form1.Fruit [I]. checked = document. form1.suoy. checked;
}
}
Function checkall (){
Var aa = 0
For (var I = 0; I <j. length; I ++ ){
If (document. form1.Fruit [I]. checked = true) aa ++;
Aa! = J. length? Document. form1.suoy. checked = false: document. form1.suoy. checked = true;
}
}
Function checkradio (){
Var a = 0
Var list = ""
For (var I = 0; I <j. length; I ++)
If (document. form1.Fruit [I]. checked = true ){
List = ""? List = document. form1.Fruit [I]. value: list = list + "," + document. form1.Fruit [I]. value;
}
If (list! = "") Alert ("your favorite fruit is" + list );

Else {
A ++;
If (a = j. length) alert ("Eldest Brother. How do you know what you like? ");}
}

</Script>
<Form name = "form1" id = "frm">
Your favorite fruit is: <br>
<Input type = checkbox value = "apple" name = "Fruit" onClick = "checkall ()">
Apple
<Input type = checkbox value = "banana" name = "Fruit" onClick = "checkall ()">
Bananas
<Input type = checkbox value = "strawberry" name = "Fruit" onClick = "checkall ()">
Strawberry
<Input type = checkbox value = "pineapple" name = "Fruit" onClick = "checkall ()">
Pineapple
<Input type = button value = "select" onclick = "checkradio ()">
<Input type = checkbox onclick = "allche ()" name = "suoy"> select all
</Form>

<Script language = "javascript" type = "text/javascript" id = "commonjs">
Function test ()
{
Fruitlist = "";
For (I = 0; I <document. getElementById ("frm"). length; I ++)
If (document. getElementById ("frm") [I]. type = "checkbox" & document. getElementById ("frm") [I]. checked)
Fruitlist + = document. getElementById ("frm") [I]. value + "";
If (fruitlist! = "")
Alert ("your favorite fruit is" + fruitlist );
Else
Alert ("big brother. How do you know what you like? ");
}
</Script>

Let's look at a more concise code and code with better effects on the check.Copy codeThe Code is as follows: <script language = "JavaScript">
<! -- Begin
Function checkAll (){
For (var j = 1; j <= 9; j ++ ){
Box = eval ("document. checkboxform. C" + j );
If (box. checked = false) box. checked = true;
}
}

Function uncheckAll (){
For (var j = 1; j <= 9; j ++ ){
Box = eval ("document. checkboxform. C" + j );
If (box. checked = true) box. checked = false;
}
}

Function switchAll (){
For (var j = 1; j <= 9; j ++ ){
Box = eval ("document. checkboxform. C" + j );
Box. checked =! Box. checked;
}
}
// End -->
</Script>
</Head>
<Body>
<Form name = checkboxform>
<Input type = checkbox name = C1> C1 <br>
<Input type = checkbox name = C2> C2 <br>
<Input type = checkbox name = C3> C3 <br>
<Input type = checkbox name = C4> C4 <br>
<Input type = checkbox name = C5> C5 <br>
<Input type = checkbox name = C6> C6 <br>
<Input type = checkbox name = C7> C7 <br>
<Input type = checkbox name = C8> C8 <br>
<Input type = checkbox name = C9> C9 <br>
<Br>
<Input type = button value = "select all" onClick = "checkAll ()"> <br>
<Input type = button value = "cancel" onClick = "uncheckAll ()"> <br>
<Input type = button value = "invert" onClick = "switchAll ()"> <br>
</Form>