1st Time to AJAX, Don't understand some line of codes
I am new to programming and its my first time to learn AJAX with PHP. I got a working sample code from internet and studying it but there are some codes that I don't understand and I am really frustrated.
In the index.php, I am so confused about the code xmlhttp.open("GET","gethint.php?q="+str,true);. I dont know what the q stands for. As far as I understand, q should stand for an html element with a name q. For example I have <input type="text" name="q" /> then I know that I have a textbox name q. But in this example I can't find any element that has a name q. Pls help...
index.php
<html>
<head>
<script type="text/javascript">
function showHint(str)
{
if (str.length==0)
{
document.getElementById("txtHint").innerHTML="";
return;
}
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","gethint.php?q="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>
<p><b>Start typing a name in the input field below:</b></p>
<form>
First name: <input type="text" onkeyup="showHint(this.value)" size="20" />
</form>
<p>Suggestions: <span id="txtHint"></span></p>
</body>
</html>
gethint.php
<?php
// Fill up array with names
$开发者_开发问答a[]="Anna";
$a[]="Brittany";
$a[]="Cinderella";
$a[]="Diana";
$a[]="Eva";
$a[]="Fiona";
$a[]="Gunda";
$a[]="Hege";
$a[]="Inga";
$a[]="Johanna";
$a[]="Kitty";
$a[]="Linda";
$a[]="Nina";
$a[]="Ophelia";
$a[]="Petunia";
$a[]="Amanda";
$a[]="Raquel";
$a[]="Cindy";
$a[]="Doris";
$a[]="Eve";
$a[]="Evita";
$a[]="Sunniva";
$a[]="Tove";
$a[]="Unni";
$a[]="Violet";
$a[]="Liza";
$a[]="Elizabeth";
$a[]="Ellen";
$a[]="Wenche";
$a[]="Vicky";
//get the q parameter from URL
$q=$_GET["q"];
//lookup all hints from array if length of q>0
if (strlen($q) > 0)
{
$hint="";
for($i=0; $i<count($a); $i++)
{
if (strtolower($q)==strtolower(substr($a[$i],0,strlen($q))))
{
if ($hint=="")
{
$hint=$a[$i];
}
else
{
$hint=$hint." , ".$a[$i];
}
}
}
}
// Set output to "no suggestion" if no hint were found
// or to the correct values
if ($hint == "")
{
$response="no suggestion";
}
else
{
$response=$hint;
}
//output the response
echo $response;
?>
In your example, q is a parameter that is passed to gethint.php with the value contained in the variable str.
The variable gets its value from the "First name" input element, whenever a key is pressed and released (the onkeyup event).
The value of q is then accessed in the PHP file by the line $q=$_GET["q"];.
You can name the parameters passed to the PHP page however you like, they don't need to correspond to HTML elements.
q is name of parameter of HTTP GET request:
Hypertext_Transfer_Protocol#Request_methods
its a LIKE A URL parameter which is simmilar to
php,
gethint.php?q=mYstring
echo $_GET['q'];// output as mYstring
In js,
var str ='mYstring';
"gethint.php?q="+str
echo $_GET['q'];// output as mYstring
i thing u can get if any problem accour add comments..pal (DO it always)
加载中,请稍侯......
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