从PHP调用Jquery

Question

having trouble calling a Jquery function from within PHP. I'm getting a syntax error when I'm using the below code:

if(!empty($_POST['selectAGE'])){
     $username = $_POST['selectAGE'];
}

if(empty($_POST['selectAGE'])){
   echo '<script type="text/javascript">'
   ,  '$("#selectAGE").prepend("<option value=''></option>").val('');'
   , '</script>';
}

Am I not escaping properly or something?

further to this, I'm then checking this select box by using

if ( form.selectAGE.selectedIndex == 0 ) { alert ( "Enter the correct Age." ); return false; }

however, once the form has been submitted, it eliminates the prepended 'empty' value and now the one you've selected is selectedindex 0. so the above check returns that you haven't entered it. How can I amend the line above to take this into account?

Answer 1

在此处转义字符：

'$("#selectAGE").prepend("<option value=\'\'></option>").val(\'\');'

Answer 2

If the escaping is giving you trouble I would just write the JS, instead of echoing it out.

if(empty($_POST['selectAGE'])): ?>
   <script type="text/javascript">
       $('#selectAGE').prepend('<option value=""></option>').val('');
   </script>
<?php endif;

I prefer using the endif instead of matching brackets between JS and PHP.

Answer 3

You need to escape the single quotes. Try this:

<?
if(!empty($_POST['selectAGE'])){
     $username = $_POST['selectAGE'];
}

if(empty($_POST['selectAGE'])){
   echo '<script type="text/javascript">',
   echo '$("#selectAGE").prepend("<option value=\'\'></option>").val(\'\');'
   , '</script>';
}
?>