我想了解並將Ajax功能應用到我的網站。但我面臨一些問題,我需要一些解釋。下面是我從w3school.com:-隨着用戶開始輸入PHP Ajax showhints
<!DOCTYPE html>
<html>
<head>
<script>
function showHint(str)
{
var xmlhttp;
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>
<h3>Start typing a name in the input field below:</h3>
<form action="">
First name: <input type="text" name="fname" id="txt1" onkeyup="showHint(this.value)" />
</form>
<p>Suggestions: <span id="txtHint"></span></p>
</body>
</html>
// and here is gethint.php code
<?php
// Fill up array with names
$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
$q=$_REQUEST["q"]; $hint="";
// lookup all hints from array if $q is different from ""
if ($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 "no suggestion" if no hint were found
// or output the correct values
echo $hint==="" ? "no suggestion" : $hint;
?>
得到一個代碼,但我有以下問題:
- 爲什麼我們使用str.length == 0?因爲我認爲這應該是 fname.length == 0
- 什麼用的q =「+ STR在 」gethint.php?Q =「 + STR一部分?
- 爲什麼我們使用$ Q = $ _ REQUEST [ 「q」],因爲我認爲這應該是 $ q = $ _ REQUEST [ 「FNAME」]
請回答這三個問題的幫助,我將不勝感激任何進一步的解釋