What steps can I take to create efficient live forms using AJAX and jQuery only?

Question

What steps can I take to create efficient live forms using AJAX and jQuery only?

I've been attempting to create AJAX forms but have had no success so far. I experimented with iframes, but found them to be not as effective. However, these are the only methods I have tried and am familiar with.

Although I attempted to use the $.AJAX function, I am unsure about the proper way to send and receive data.

I also explored the AJAX load function, but struggled with understanding how to send data through it.

Various pure JavaScript approaches were also tested, but they proved to be too complicated.

Furthermore, I am seeking guidance on how to retrieve variables from the server in order to change the text box color to red and display errors properly.

php ajax

Answer 1

Answer №1

If you want to make an ajax request, follow these steps:

Here is the JQUERY code for sending an ajax request to the server:

$.ajax({ method:"POST" url:"form.php", data: $("form").serialize(), dataType: 'json', success: function() {
    
    // Add your code to run in case of success
    
},
    
error: function() {
        
    // Add your code to run on an error
        
}

});

To return the data back, use this PHP code to output the data as json:

PHP code to send data back in JSON format:

// Make sure that the data is in array format to send multiple pieces of information
echo json_encode($data);

Retrieve data from the client using this PHP code:


$_REQUEST['username'];

In order to access and read the returned json data in JS, add this code within the success function:

JS code to access the returned JSON data from the server:


   data.name
 // ^     ^     ^
 // The first pointer refers to the PHP variable
 // The second pointer indicates the array offset

Answer 2

If you want to make an ajax request, follow these steps:

Here is the JQUERY code for sending an ajax request to the server:

$.ajax({ method:"POST" url:"form.php", data: $("form").serialize(), dataType: 'json', success: function() {
    
    // Add your code to run in case of success
    
},
    
error: function() {
        
    // Add your code to run on an error
        
}

});

To return the data back, use this PHP code to output the data as json:

PHP code to send data back in JSON format:

// Make sure that the data is in array format to send multiple pieces of information
echo json_encode($data);

Retrieve data from the client using this PHP code:


$_REQUEST['username'];

In order to access and read the returned json data in JS, add this code within the success function:

JS code to access the returned JSON data from the server:


   data.name
 // ^     ^     ^
 // The first pointer refers to the PHP variable
 // The second pointer indicates the array offset

Answer 3

Answer №2

Here is a straightforward example to demonstrate how you can search for names using keywords.

search.php

<?php
// List of names
$a[] = "Anna";
$a[] = "Brittany";
$a[] = "Cinderella";
$a[] = "Diana";
$a[] = "Eva";

// Get the 'q' parameter from URL
$q = $_REQUEST["q"];

$hint = "";

// Check if $q is not empty and find matches in the array
if ($q !== "") {
  $q = strtolower($q);
  $len=strlen($q);
  foreach($a as $name) {
    if (stristr($q, substr($name, 0, $len))) {
      if ($hint === "") {
        $hint = $name;
      } else {
        $hint .= ", $name";
      }
    }
  }
}
// Output suggestions or "no suggestion" if no hint found
echo $hint === "" ? "no suggestion" : $hint;
?>

home.html

<script>
function displayHint(str) {
  if (str.length == 0) {
    document.getElementById("txtHint").innerHTML = "";
    return;
  } else {
    var xmlhttp = new XMLHttpRequest();
    xmlhttp.onreadystatechange = function() {
      if (this.readyState == 4 && this.status == 200) {
        document.getElementById("txtHint").innerHTML = this.responseText;
      }
    }
    xmlhttp.open("GET", "search.php?q="+str, true);
    xmlhttp.send();
  }
}
</script>
<p><b>Start typing a name in the input field below:</b></p>
<form action="">
  <label for="fname">First name:</label>
  <input type="text" id="fname" name="fname" onkeyup="displayHint(this.value)">
</form>
<p>Suggestions: <span id="txtHint"></span></p>

Answer 4

Here is a straightforward example to demonstrate how you can search for names using keywords.

search.php

<?php
// List of names
$a[] = "Anna";
$a[] = "Brittany";
$a[] = "Cinderella";
$a[] = "Diana";
$a[] = "Eva";

// Get the 'q' parameter from URL
$q = $_REQUEST["q"];

$hint = "";

// Check if $q is not empty and find matches in the array
if ($q !== "") {
  $q = strtolower($q);
  $len=strlen($q);
  foreach($a as $name) {
    if (stristr($q, substr($name, 0, $len))) {
      if ($hint === "") {
        $hint = $name;
      } else {
        $hint .= ", $name";
      }
    }
  }
}
// Output suggestions or "no suggestion" if no hint found
echo $hint === "" ? "no suggestion" : $hint;
?>

home.html

<script>
function displayHint(str) {
  if (str.length == 0) {
    document.getElementById("txtHint").innerHTML = "";
    return;
  } else {
    var xmlhttp = new XMLHttpRequest();
    xmlhttp.onreadystatechange = function() {
      if (this.readyState == 4 && this.status == 200) {
        document.getElementById("txtHint").innerHTML = this.responseText;
      }
    }
    xmlhttp.open("GET", "search.php?q="+str, true);
    xmlhttp.send();
  }
}
</script>
<p><b>Start typing a name in the input field below:</b></p>
<form action="">
  <label for="fname">First name:</label>
  <input type="text" id="fname" name="fname" onkeyup="displayHint(this.value)">
</form>
<p>Suggestions: <span id="txtHint"></span></p>

What steps can I take to create efficient live forms using AJAX and jQuery only?

Answer №1

Answer №2

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