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JavaScript determines whether a radio box or check box is selected method Collection _ form Effects

Source: Internet
Author: User
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Tip: The purpose of the Getemementsbyname method is to get a collection of objects based on the value of the NAME tag property.
Sample One <meta http-equiv= "Content-type" content= "text/html; charset=gb2312 ">
<title> Determine if the Radio box or check box is selected </title>

<body>
<input name= "Radio1" type= "Radio" value= "Test" >
<button onclick= "alert" (' Single option ' + (document.getelementsbyname (' Radio1 ') [0].checked? ": ' no ') + ' selected '" > Test </button><br>
<input name= "Radio1" type= "Radio" value= "Test" >
<button onclick= "alert" (' Single option ' + (document.getelementsbyname (' Radio1 ') [1].checked? ': ' No ') + ' selected ') ' > Test </ Button><br>

<input name= "CheckBox1" type= "checkbox" value= "Test" >
<button onclick= "alert" (' Multiple options ' + (Document.getelementsbyname (' CheckBox1 ') [0]. Checked? ': ' No ') + ' selected ') ' > Test </ Button><br>
<input name= "CheckBox1" type= "checkbox" value= "Test" >
<button onclick= "alert" (' Multiple options ' + (Document.getelementsbyname (' CheckBox1 ') [1].checked? ': ' No ') + ' selected ') ' > Test </ Button>

Tip: The purpose of the Getemementsbyname method is to get a collection of objects based on the value of the NAME tag property.
</body>
Sample two:

<form name= "MyForm" action= "method=" "onsubmit=" return Check () ">
<input type= "Radio" name= "Picno" value= "1" >
<input type= "Radio" name= "Picno" value= "2" >
<input type= "Radio" name= "Picno" value= "3" >
<input type= "Submit" value= "Submit" >
</form>
<script language= "JavaScript" ....
function Check () ... {
var flag=0
for (i=0;i<myform.picno.length;i++)
if (myform.picno[i].checked==true) ... {
Flag=1
Break
}
if (!flag) ... {
Alert ("Choose where to replace the picture first")
return False
}
}
</script>

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