POSTDATA没有使用javascript submit（）函数传递

Question

I'm trying to write a form that will update the hidden field values and then submit, after which the values will be input into the mysql database. However, while the form does seem to submit, the $_POST array seems to be empty and i get "unidentified index" errors whenever i try to access any of the $_POST elements??

The relevant code is as follows:

<?php
if(isset($_GET['a'])){
$title = $_POST['left'];
$sql = "UPDATE boxes SET topx = '".$_POST['left']."', topy = '".$_POST['top']."', width = '".$_POST['width']."', height = '".$_POST['height']."' WHERE id = '2'";
    // this is where I get "unidentified index" errors
mysql_query($sql);
}
else {
$title = "test";
}
?>

the JS function to fill the hidden fields and submit the form:

<script type = "text/javascript">
function dosmt(form){
JStopx = dd.elements.field2.x; alert(JStopx);
JStopy = dd.elements.field2.y; alert(JStopy);
JSwidth = dd.elements.field2.w; alert(JSwidth);
JSheight = dd.elements.field2.h; alert(JSheight);
alert("test2");

alert(document.getElementById('top').value);
document.getElementById('top').value = JStopy; alert("test1");
document.getElementById('left').value = JStopx;
document.getElementById('width').value = JSwidth;
document.getElementById('height').value = JSheight;
alert("waah");
location = "http://127.0.0.1/experiment/index.php?a=true";
alert ("OK"); 
document.getElementById('testform').submit();
}
</script>

and the form:

<form name = 'testform' method = "post" id = 'testform' action = "index.php">
<input type = "hidden" name = 'top' id = 'top' value = ''/>
<input type = "hidden" name = 'left' id = 'left' value = ''/>
<input type = "hidden" name = 'width' id = 'width' value = ''/>
<input type = "hidden" name = 'height' id = 'height' value = ''/>
<input type = "hidden" name = 'placeholder' id = 'placeholder' value = 'blah'/>
<input type = "button" name = 'update' id = 'update' value = "Update" onClick = 'dosmt(this.form)'>
</form>

Any help would be appreciated, thanks!

Answer 1

You shouldn't use location in JavaScript; if you do something like

location='http://example.com'

you're actually redirecting the page to example.com.

You should remove the line

location = "http://127.0.0.1/experiment/index.php?a=true";

and change it to something like:

document.getElementById('testform').action="http://127.0.0.1/experiment/index.php?a=true";

• Read more about the location variable

Answer 2

When you submit your form, you go to index.php , not index.php?a=true - try doing

location = "http://127.0.0.1/experiment/index.php?a=true";
document.getElementById('testform').action = location;

Answer 3

Replace

<input type = "button" name = 'update' id = 'update' value = "Update" onClick = 'dosmt(this.form)'>

with

<input type = "button" name = 'update' id = 'update' value = "Update" onClick = 'dosmt(document.testform)'>