Function doesn't execute from an onclick insid

2019-02-27 02:13发布

问题:

This question already has an answer here:

  • JavaScript not running on jsfiddle.net 4 answers

this is probably stupidly easy but I'm very new to JavaScript and it's driving me nuts.

My question, why doesn't this work: http://jsfiddle.net/Ye9tG/

<input type="button" id="butt" value="Button" onclick="getThought();"/>

It works fine if I add the onclick directly into the JavaScript:

document.getElementById("butt").onclick = getThought;

Thanks in advance.

回答1:

Your getThoughts function isn't defined, because your JavaScript is set to execute onLoad. See the dropdown menu in the upper left of jsFiddle. Select "No wrap - in <head>" to resolve the issue: http://jsfiddle.net/Ye9tG/1/

Also, always take a look at your browser's console to check for errors. In this case, you'll see a Uncaught ReferenceError: getThought is not defined error when clicking the button.



回答2:

In the top left corner of jsfiddle you'll see that your fiddle is set to run your js code "onLoad". What that really means is that jsfiddle creates this for you:

<script type='text/javascript'>//<![CDATA[ 
window.onload=function(){

// YOUR CODE HERE

}//]]>  

</script>

As a result, your function is only accessible within that onload function. Change the value to "no wrap head" and you'll see that it works.

Your other option would be to make your function explicitly global:

window.getThought = function(){
  // ...

http://jsfiddle.net/Ye9tG/5/