jQuery无法在wordpress的footer.php文件中工作？

Question

I have to include these code inside the footer.php file of wordpress but it is not working ,

<script type="text/javascript">
    jQuery('#vpb_captcha_code_102').blur(function(){
       var value= jQuery('#vpb_captcha_code_102').val();
      alert(value);
  });
</script>

Whereas if i try to run this same code from console it works, please let me know what should i do.

Answer 1

A page can't be manipulated safely until the document is "ready." jQuery detects this state of readiness for you.

Please make changes in code as:

<script type="text/javascript">
jQuery( document ).ready(function() {
    jQuery('#vpb_captcha_code_102').blur(function(){
       var value= jQuery('#vpb_captcha_code_102').val();
      alert(value);
  });
});
</script>

https://www.w3schools.com/jquery/