Uncaught TypeError: Cannot read property 'undefined' of undefined
Question
I have problem with select tag. I google it and didn't find any solution regarding my question. here is one of the link... ( Uncaught TypeError: Cannot read property 'value' of undefined )..... I have function on onchange event in the select tag some how like this..
<select id="selectBox" onchange="_change();">
<?php
$i = 1;
while ($lastpage >= $i):?>
<option><?php echo $i; ?></option>
<?php
$i++;
endwhile;
?>
</select>
Possible jQuery code ...
<script type="text/javascript">
function _change(evt)
{
alert(this.options[this.selectedIndex].value);
};
</script>
The question is Why I am getting undefined of undefined instead getting a value or property undefined so that I can go ahead and solve that prob... Thanks any help would more be appreciated...
2 answers
solution1
1 ACCPTED 2014-11-10 11:48:05
You have to pass the referrer element this to your javascript function.
Code:
<select id="selectBox" onchange="_change(this);">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
js:
function _change(el) {
alert(el.options[el.selectedIndex].value);
};
solution2
0 2014-11-10 11:50:46
***SIMPLEST REPRESENTATION:-***
<!DOCTYPE html>
<html>
<body>
Select a fruit and click the button:
<select id="mySelect">
<option value="11">Apple</option>
<option value="12">Orange</option>
<option value="13">Pineapple</option>
<option value="14">Banana</option>
</select>
<button type="button" onclick="myFunction()">Display index</button>
<script>
function myFunction() {
var x = document.getElementById("mySelect").selectedIndex;
var y = document.getElementById("mySelect").options;
alert("Index: " + y[x].index + " text is " + y[x].text + " and value is " + y[x].value);
}
</script>
</body>
</html>
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