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I'm trying to call a function by name .onchange of a select but nothing happens. When the function is describled after the attribute, it works.
THIS DOESN'T WORK
HTML:
<select id="numb">
<option value="1">1</option>
<option value="2">2</option>
</select>
SCRIPT:
<script type="text/javascript">
$('#numb').change(testMessage);
</script>
<script type="text/javascript">
function testMessage(){
alert('Hello');
}
</script>
THIS WORKS
HTML:
<select id="numb">
<option value="1">1</option>
<option value="2">2</option>
</select>
SCRIPT:
<script type="text/javascript">
$('#numb').change(function(){
alert('Hello')
});
</script>
EDIT:
Ok, for all those who said me to include the function on the same script. This is not possible because the testMessage() function is in an external .js script included on the <head> of the HTML.
442
You can name each function according to the div 's id and call it dynamically using the object["methodName"]() syntax to call it.
Answer: Use the jQuery :selected Selector You can use the jQuery :selected selector in combination with the val() method to find the selected option value in a select box or dropdown list.
It is because the handler testMessage is not defined when binding it to the change event.
It should work if it was in the same script context like below,
<script type="text/javascript">
$('#numb').change(testMessage);
function testMessage(){
alert('Hello');
}
</script>
Code inside <script></script> are executed one by one progressive from top and testMessage function doesn't exist inside the first <script></script>.
You have couple of options here,
Put it inside an anonymous function which will let your script to resolve the testMessage function later. [As suggested in Optimus Prime answer]
<script type="text/javascript">
$('#numb').change(function () {
testMessage
});
</script>
<script type="text/javascript">
function testMessage(){
alert('Hello');
}
</script>
Include the script that has testMessage function above the script that binds the testMessage like below,
<script type="text/javascript">
function testMessage(){
alert('Hello');
}
</script>
<script type="text/javascript">
$('#numb').change(testMessage);
</script>
Instead try ,
<script type="text/javascript">
$('#numb').change(function(){
testMessage();
});
</script>
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