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POProblem with Javascript, AJAX & JSON
primarykey
Id
7057335
data
AcceptedAnswerId
7057422
AnswerCount
5
ClosedDate
CommentCount
9
CommunityOwnedDate
CreationDate
2011-08-14T14:19:26.853
FavoriteCount
1
LastActivityDate
2011-08-14T14:40:21.013
LastEditDate
2011-08-14T14:35:01.107
LastEditorUserId
560648
OwnerUserId
840973
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0
PostTypeId
1
Score
0
ViewCount
303
LastEditorDisplayName
text
Body
I'm an iPhone Developer whose quite new to web development so please forgive me if I'm making silly mistakes here: What I'm trying to accomplish is when the user selects an item from a drop-down, it calls some javascript, which sets off an AJAX request to a PHP file I have which returns some JSON. - That JSON includes a thumbnail image filename, and a caption for the image. These need to be passed in to an image, and textfield respectively in my document. The problem is, it fails after trying to eval the json. - The same happens with <code>eval(json);</code> and <code>JSON.parse(json);</code> I worked this out by calling document.write('something'); periodically in my response method. - It will always be able to write up to the point where it parses the json. I am sure my PHP is valid and my request is good (I can output the response from the JS fine). Here is the function I call when a new item is selected in the drop-down: <pre><code>function changeImage(id){ var xmlhttp; 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) { var res=xmlhttp.responseText; var responseObject = eval(res); var caption = responseObject.caption; var textField = document.getElementById('caption'); textField.value = caption; var imagePreview = document.getElementById('imgPreview'); imagePreview.src = responseObject.filename; } } xmlhttp.open("GET","getCaption.php?id="+id,true); xmlhttp.send(); } </code></pre> When I output res (or access the php file manually) the JSON looks like this: <pre><code>{"caption":"A caption","filename":"myimage_thumb.jpg"} </code></pre> why is the JSON eval failing? UPDATE: This error is logged: <code>SyntaxError: Parse error</code>
Tags
<php><javascript><ajax><json><xmlhttprequest>
Title
Problem with Javascript, AJAX & JSON
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1. PO
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1. USLightness Races in Orbit
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1. USAlex Coplan
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