Pre-fill a form (no control over form code) - php

Question

I'm using a form plugin / addon where I don't have control over how the form is generated.
The form generates HTML which looks like this:
<form>
<label>First Name</label><input name="Question25" type="text" value="" />
<input class="formBlockSubmitButton" name="add" type="submit" value="Submit" />
</form>
I would like to prefill some of the form values but I can't write, say
<input name="Question25" type="text" value="<?php echo $my_value; ?>" />
Because the form addon generates that HTML. I can write PHP or Javascript before this block, is there a way to search for an input with a name of "Question25" and then prefill it when the block comes up?

Answer 1

You could use jQuery and the .val() method:
<script type="text/javascript">
$(function() {
$('input[name="Question25"]').val('some value');
});
</script>
and if the value must come from the server:
<script type="text/javascript">
$(function() {
var obj = <?php echo json_encode(array('value' => $my_value)); ?>;
$('input[name="Question25"]').val(obj.value);
});
</script>

Answer 2

You can emit all the values you'd like to search as an array of fieldname/values, and then emit a function that tries to map those values to those fields.
<script type="text/javascript">
var values = [{fieldName:'Question25', value:'MyValue'}]; // iterate through your values in PHP and generate the {fieldName:'value',value:'value'} object
$(function() {
$.each(values, function(index, item) {
$('input[name=' + item.fieldName + ']').val(item.value);
});
});
</script>

Answer 3

var value='<?php echo $my_value; ?>'
$("input:text[name='Question25']").val(value);
use something like this

Answer 4

Use Javascript. With jQuery, you could do something along the lines of:
$("input[name=Question25]").val(my_value);
You can then insert PHP vairables into the Javascript with echo, load them with AJAX, or whatever you need.