Trouble with JS form elements
I've built a form with a checkbox and a few text fields and I've set it up so that a user can add additional occurrences of this set of elements. I've done this by creating a div containing these elements with display set to 'none.' Javascript then clones and displays this div as needed (once if no $_POST data; once for user click; x times if there is $_POST data). The Javascript also labels the elements uniquely and sequentially - I've set it up to read in to a serialized array for eventual MySQL insertion - "occurrence[integer][name]".
So far, so good. Everything behaves as it should and $_POST output is exactly what I need for MySQL.
My trouble is coming in trying to display the $_POST data within the form elements. In the code below, I've got a JS variable set to PHP $_POST data - which actually works, so long as I use static code without any variables. In other words,
newField[i].value ='<?php echo $_POST[occurrence][1][start_date]; ?>';
does indeed display that value (albeit in every field). And obviously
newField[i].value ='['+counter+']['+theName+']';
correctly displays that field's counter and name. But when I try to combine like so is when I get nothing
newField[i].value ='<?php echo $_POST[occurrence]['+counter+']['+theName+']; ?>';
Here's my full code:
<?php
$occ_count = count($_POST['occurrence']);
?>
<script type="text/javascript">
var counter = 0;
function moreFields() { // this function clones the div containing the elements and allows it to display
counter++;
var newFields = document.getElementById('readroot').cloneNode(true);
newFields.id = '';
newFields.style.display = 'block';
var newField = newFields.childNodes;
for (var i=0;i<newField.length;i++) {
var theName = newField[i].name
if (theName) {
newField[i].name = 'occurrence['+counter+']['+theName+']';
}
newField[i].value ='<?php echo $_POST[occurrence]['+counter+']['+theName+']; ?>';
}
var insertHere = document.getElementById('writeroot');
insertHere.parentNode.insertBefore(newFields,insertHere);
}
function addLoadEvent(func) { // this function allows multiple functions to be called on page load
var oldonload = window.onload;
if (typeof window.onload != 'function') {
window.onload = func;
} else {
window.onload = function() {
if (oldonload) {
oldonload();
}
func();
}
}
}
// this bit determines how many times the moreFields function should be called, based on $_POST data
var occ_count = "<?php echo $occ_count; ?>";
if(occ_count == 0) {window.onload = moreFields;}
else if(occ_count >= 1) {
for (var n=0;n<occ_count;n++) {
addLoadEvent(moreFields);
}
}
</script>
</head>
<body>
<h2>JS test2</h2>
<div id="readroot" style="display: none">
<label for="all_day">All Day</label>
<input type="checkbox" name="all_day"
onClick="allday(this, this.form)"/>
<label for="start_date">From:</label>
<input type="text" name="start_date"
value="" size="15" />
<label for="start_time"></label>
<input type="text" 开发者_如何转开发name="start_time"
value="" size="15" />
<label for="end_date">To:</label>
<input type="text" name="end_date"
value="" size="15" />
<label for="end_time"></label>
<input type="text" name="end_time"
value="" size="15" />
<a href="javascript:;" onclick="this.parentNode.parentNode.removeChild(this.parentNode);">Delete</a>
<br /><br />
<hr style="border: 0;color: #ddd;background-color: #ddd;height: 1px;">
</div> <!--readroot-->
<form method="post" >
<span id="writeroot"></span>
<p id="addnew"><a href="javascript:moreFields()">Add New</a></p>
<input type="submit" value="Send form" />
</form>
<hr>
<?php if($_POST) : ?>
<?php // this is purely for troubleshooting
echo 'count: '.count($_POST['occurrence']).'<br />';
foreach ( $_POST as $varname => $postitem ) {
echo 'name: '.$varname.' value: ';
print_r($postitem);
echo '<br />';
}
?>
<?php endif; ?>
</body>
I can't figure out if this is just a syntax issue or just structurally impossible. I know JS is supposed to load after PHP but yet I can get that JS variable to produce php $_POST data so there's something going on. Obviously, I'm confused. But I'm also open to any other (even completely different) ideas on how to accomplish what I need.
Thanks for any thoughts, ideas or suggestions!
As @Mark states, you're trying to concatenate server-side PHP with client-side Javascript - this simply isn't going to work. Everything within your <?php and ?> tags will be evaluated before the page is ever sent to the client - so the actual PHP code will be this:
echo $_POST['occurrence']['+counter+']['+theName+'];
I'd guess this actually tries to look up keys called '+counter+' and ``'+theName+' in your PHP array, and of course these don't exist.
There are a couple of ways to do this right - my guess is that the easiest would be to dump the PHP into a javascript variable:
var postOccurrence = <?php echo json_encode($_POST['occurrence']); ?>;
Then update your code in the Javascript loop to:
newField[i].value = postOccurrence[counter][theName];
The other easy option would be to do the loop in PHP, rather than Javascript, and have it output static Javascript code for fields from 0 to n.
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