Javascript form & Ajax request to PHP_问答_开发者

开发者 https://www.devze.com 2023-02-21 07:54 出处：网络

Why is this not working? When the Ajax code IS NOT wrapped in function xmlhttpGet() it does work: PHP returns the called page and inserts it into the DIV. In this code i have wrapped the code into the

相关专题：javascript php

Why is this not working? When the Ajax code IS NOT wrapped in function xmlhttpGet() it does work: PHP returns the called page and inserts it into the DIV. In this code i have wrapped the code into the function xmlhttGet() amd nothing happens. The requested page is not loaded into the DIV.

<html><head><title>AJAX GET </title>


</head><body><center />
<h1>Loading a web page into a DIV</h1>
<FORM id="form" method="post" action="">

<b> Enter argument: </b>
<input size="40" name="q" id="q" value="">
<INPUT TYPE="submit" id="submit" VALUE="Submit" onClick="xmlhttpGet(this.form)">
<INPUT TYPE="reset" VALUE="Reset">
</FORM>

<div id='info'>This sentence will be replaced</div>

<script>

function xmlhttpGet(form)
{

    nocache = "&nocache=" + Math.random() * 1000000
    request = new ajaxRequest()

    var $q = form.q.value

    request.open("GET", "urlget.php?url=amazon.com/gp/aw" + nocache, true)

    request.onreadystatechange = function()
    {
        if (this.readyState == 4)
        {
            if (this.status == 200)
            {
                if (this.responseText != null)
                {
                    document.getElementById('info').innerHTML =
                        this.responseText
                }
                else alert("Ajax error: No data received")
            }
            else alert( "Ajax error: " + this.statusText)
        }
    }

}// END xmlhttp开发者_开发知识库Get

request.send(null) ;

function ajaxRequest()
{
    try
    {
        var request = new XMLHttpRequest()
    }
    catch(e1)
    {
        try
        {
            request = new ActiveXObject("Msxml2.XMLHTTP")
        }
        catch(e2)
        {
            try
            {
                request = new ActiveXObject("Microsoft.XMLHTTP")
            }
            catch(e3)
            {
                request = false
            }
        }
    }
    return request
}// ajaxRequest


</script></body></html>

[EDIT]

the onClick is triggered fine. I have verified by inserting alerts into the functions.

[EDIT2]

i suppose it would help if i show the PHP bit too

<?php // urlget.php

if (isset($_GET['url'])) {
    echo file_get_contents("http://".sanitizeString($_GET['url']));
}
else {
        echo "problem!" ; // [edited line]
    }

function sanitizeString($var) {
    $var = strip_tags($var);
    $var = htmlentities($var);
    return stripslashes($var);
}
?>

you have to call xmlhttpGet() somewhere in ur script to get it to 'run'

When your code is not wrapped in a function, it will simply execute as the code is parsed by the browser.

Once you wrap it in a function, it will not execute until the function is explicitly called.

If you want to get the script to run automatically, try changing your body tag to:

<body onload='xmlhttpGet();'>

If you want to fire the function with user interaction, use one of the many events such as onclick or onmouseover or onmousedown

Your xmlhttpget function should start as:

function xmlhttpGet(form)
{

... as it is you're referencing the variable form in the function (eg var $q = form.q.value) but never assigning it a value (so it's being created/pulled from global scope).

The scope of this in your function for onreadystatechange will vary wildly depending on browser and how it's called - not a good design decision, try replacing this with request in the function.