Using Ajax to pass Json variable and decode

Question

I have a AJAX script which i was using previously and was able to retrieve data from viewCommentsJson.php as such[{"comments":"Greta"},{"comments":"John"}]. I was wondering if its able to decode the return value such that it display it properly ?

Thanks in advance

Greta
John

Main.php

<a onclick="showUser('.$row['ID'].')" method = "POST" action= "viewCommentsJson.php">Show Comments</a> <script> function showUser(str) { if (str=="") { 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("Post","viewCommentsJson.php?q="+str,true); xmlhttp.send(); } </script>

viewCommentsJson.php

$com = $_REQUEST["q"]; include 'connectDatabase.php'; //opening sql table $selected = mysql_select_db("2000",$dbhandle) or die("Could not select 2000"); $arr = array(); $data = mysql_query("SELECT comments FROM comment WHERE ID = '$com'"); $rows = array(); while($r = mysql_fetch_assoc($data)) { $rows[] = $r; } print json_encode($rows);

asprin · Accepted Answer · 2014-05-19 07:07:34Z

1

Since you don't mind a jQuery solution, here is how it can be done

function showUser(str) { if (str=="") { document.getElementById("txtHint").innerHTML=""; return; } $.ajax({ type:'post', url: 'viewCommentsJson.php', data:{q:str}, success:function(data) { data = $.parseJSON(data); var response; $.each(data, function(index, value){ response += value+'<br />'; }); $('#txtHint').html(response); } }); }

You can refer $.ajax and $.parseJSON for more information.

Note: Your SELECT comments FROM comment WHERE ID = '$com' is prone to SQL injection. At the very least, you should sanitize all incoming data before using it in your query directly.

edited May 19, 2014 at 7:07

answered May 19, 2014 at 6:05

asprin

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7 Comments

user2691544 Over a year ago

Hey thanks for the help. However i ran into a problem after replacing with your script. ReferenceError: showUser is not defined. I do not understand why showUser is not defined given that the function is being declared.

asprin Over a year ago

Try putting your <script> tag above your <a onclick..... tag. Also, an anchor tag shouldn't have method and action attributes so you can remove them from the <a> tag too

user2691544 Over a year ago

I am sorry i cant add the <script> tag above <a onclick..... it will render my button invisible. Also i will be needing to pass the value .$row['ID']. into $com = $_REQUEST["q"];

asprin Over a year ago

Why would it make your button invisible? It won't and it shouldn't

user2691544 Over a year ago

I am assuming you are talking about encapsulating the <a onClick...> with the script tag as such right ? <script><a onclick="showUser('.$row['ID'].')">Show Comments</a></script>

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Vikram · Accepted Answer · 2014-05-19 07:13:06Z

<a onclick="showUser('1')" href="#?">Show Comments</a> <script> function showUser(str) { if (str=="") { 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) { data = eval(xmlhttp.responseText); for(i=0;i<data.length;i++){ document.getElementById("txtHint").innerHTML = document.getElementById("txtHint").innerHTML + data[i].comments; } } } xmlhttp.open("Post","viewCommentsJson.php?q="+str,true); xmlhttp.send(); } </script> <div id="txtHint"></div>

First of all remove method and action from A tag and used above code now. Removed some typos

Thank you very much for helping me out. I got an Uncaught syntaxerror: unexpected identifier error.Any idea where i might have screw up again ?

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