HTML PHP Progress Bar

I have a websi开发者_如何学Cte with a form that uses PHP to send the form data. Is there a way to create a progress bar on the page that looks like it is in action, so that people don't click the button more than once after it's clicked and sending the PHP information.

Thanks.

---

Progress Bar: Simple Text Version :

<?php
// Output a 'waiting message'
echo 'Please wait while this task completes';

// Now while waiting for a certain task to
// complete, keep outputting .'s

while (true) {
  // Echo an extra dot, and flush the buffers
  // to ensure it gets displayed.
  echo ' .';
  flush();

  // Now sleep for 1 second and check again:
  sleep(1);
}
?>

Progress Bar: PHP-Based (grphical) :

<?php
// A function that will create the initial setup
// for the progress bar: You can modify this to
// your liking for visual purposes:
function create_progress() {
  // First create our basic CSS that will control
  // the look of this bar:
  echo "
<style>
#text {
  position: absolute;
  top: 100px;
  left: 50%;
  margin: 0px 0px 0px -150px;
  font-size: 18px;
  text-align: center;
  width: 300px;
}
  #barbox_a {
  position: absolute;
  top: 130px;
  left: 50%;
  margin: 0px 0px 0px -160px;
  width: 304px;
  height: 24px;
  background-color: black;
}
.per {
  position: absolute;
  top: 130px;
  font-size: 18px;
  left: 50%;
  margin: 1px 0px 0px 150px;
  background-color: #FFFFFF;
}

.bar {
  position: absolute;
  top: 132px;
  left: 50%;
  margin: 0px 0px 0px -158px;
  width: 0px;
  height: 20px;
  background-color: #0099FF;
}

.blank {
  background-color: white;
  width: 300px;
}
</style>
";

  // Now output the basic, initial, XHTML that
  // will be overwritten later:
  echo "
<div id='text'>Script Progress</div>
<div id='barbox_a'></div>
<div class='bar blank'></div>
<div class='per'>0%</div>
";

  // Ensure that this gets to the screen
  // immediately:
  flush();
}

// A function that you can pass a percentage as
// a whole number and it will generate the
// appropriate new div's to overlay the
// current ones:

function update_progress($percent) {
  // First let's recreate the percent with
  // the new one:
  echo "<div class='per'>{$percent}
    %</div>\n";

  // Now, output a new 'bar', forcing its width
  // to 3 times the percent, since we have
  // defined the percent bar to be at
  // 300 pixels wide.
  echo "<div class='bar' style='width: ",
    $percent * 3, "px'></div>\n";

  // Now, again, force this to be
  // immediately displayed:
  flush();
}

// Ok, now to use this, first create the
// initial bar info:
create_progress();

// Now, let's simulate doing some various
// amounts of work, and updating the progress
// bar as we go. The usleep commands will
// simulate multiple lines of code
// being executed.
usleep(350000);
update_progress(7);
usleep(1550000);
update_progress(28);
usleep(1000000);
update_progress(48);
usleep(1000000);
update_progress(68);
usleep(150000);
update_progress(71);
usleep(150000);
update_progress(74);
usleep(150000);
update_progress(77);
usleep(1150000);
update_progress(100);

// Now that you are done, you could also
// choose to output whatever final text that
// you might wish to, and/or to redirect
// the user to another page.
?>

---

Progress bars on web content are hard to get right because you don't know the total time the process will take and you don't have progress indicators from the process to let you know when to update your bar. You might be better off using a spinning loading image like the ones available on ajaxload.com.

You can make a hidden div cover the whole page and activate the div in your javascript when you're waiting.

In your html:

<div style="display:none;" id="wait"></div>

in the css:

#wait {
   position:fixed;
   top:50%;
   left:50%;
   background-color:#dbf4f7;
   background-image:url('/images/wait.gif'); // path to your wait image
   background-repeat:no-repeat;
   z-index:100; // so this shows over the rest of your content

   /* alpha settings for browsers */
   opacity: 0.9;
   filter: alpha(opacity=90);
   -moz-opacity: 0.9;
}

And then in your JavaScript:

...
$("#wait").show(); // when you want to show the wait image
...
$("#wait").hide(); // when your process is done or don't worry about it if the page is refreshing

---

You'll need to use Javascript, I recommend you to take a look at JQuery's ProgressBar.