How does JS get the selected value of the radio and not the selected value of the radio

2020-03-26 21:43:27
OfStack

The following is an article taken off the web (untested but very standard to imitate)

 
<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=gb2312"> 
<title>text</title> 
<script> 
var chk = 0; 
window.onload=function (){ 
var chkObjs = document.getElementsByName("radio"); 
for(var i=0;i<chkObjs.length;i++){ 
if(chkObjs[i].checked){ 
chk = i; 
break; 
} 
} 
} 
function check_radio(){ 
var chkObjs = document.getElementsByName("radio"); 
for(var i=0;i<chkObjs.length;i++){ 
if(chkObjs[i].checked){ 
if(chk == i){ 
alert("radio No change in value can be committed "); 
break; 
} 
} 
} 
} 
</script> 
</head> 
<body> 
<form action='' method='post' onsubmit='javascript:return check_radio()'> 
<input type='radio' value='1' name='radio' checked='checked'> one ; 
<input type='radio' value='2' name='radio'> two ; 
<input type='radio' value='3' name='radio'> three ; 
<input type='radio' value='4' name='radio'> four ; 
<input type='radio' value='5' name='radio'> five ; 

<input type=submit value=sub > 
</form> 
</body> 
</html>

The following is to get the value of the radio without making a choice

 
<input type="radio" name="money" value="1" /> The dollar  
<input type="radio" name="money" value="2" /> The Japanese yen  
<input type="radio" name="money" value="3" /> The euro

Native JS mode :(native DOM manipulation treats text as a node, so there will be nextSibling)

 
var  The dollar  = document.getElementsByName("money")[0].nextSibling.nodeValue; 
var  The Japanese yen  = document.getElementsByName("money")[1].nextSibling.nodeValue; 
var  The euro  = document.getElementsByName("money")[2].nextSibling.nodeValue;

JQuery way

 
$('input[name="money"]:checked').next('span').html(); 

<input type="radio" name="money" value="1" checked="checked" /><span> The dollar </span> 
<input type="radio" name="money" value="2" /><span> The Japanese yen </span> 
<input type="radio" name="money" value="3" /><span> The euro </span> 

<!-- Normally, creating checkboxes or checkboxes is used label Link it, for example: --> 
<input id="radio1" type="radio" name="money" value="1" /><label for="radio1"> The dollar </label>

The following should be selected:

This one just determines if there is a choice

 
function radioValue(){ 
var radArr = document.getElementsByName("radiov"); 
var radValue = ""; 
//alert(radArr.length); 
for(var i=0; i<radArr.length; i++){ 
//alert(radArr[i].checked+" "+radArr[i].name + " "+ radArr[i].value); 
if(radArr[i].checked){ 
radValue = radArr[i].value; 

} 
} 

if(radValue != null && radValue != ""){ 
alert(radValue); 
}else{ 
alert(" Please select a "); 
} 

}

< Input type="button" value=" get data from test radio "onclick="radioValue();" / >