Ask a Jedi: Trouble with ColdFusion.Ajax.SubmitForm

Andy asks:

This is probably a stupid question but I can't seem to get this to work. I'm using a ColdFusion.Ajax.submitForm and I thought that I would be able to return something from the form's submit handler page using my callback function. I can't seem to get this to work. I tried to a variable on the submit handler page to give it back to the caller page where the form lives but I just get a giant javascript dialog when I try to test this out using an alert in the callback function to display my callbackMsg. Should I be taking a different approach? I really need to get the primary key of the newly inserted record back and can't seem to return it to the calling page. </p> </blockquote> Now now, Andy, as we all know, there are no stupid questions, just stupid programming languages. That being said, I have a good idea of what you are running into. Let's start with a super simple example. I'll build a form with two text fields. These fields will represents two numbers. A third field will be used for the answer. Finally I'll add a button: <form id="myform"> <input type="text" name="number1"> + <input type="text" name="number2"> = <input type="text" id="result"> <input type="button" value="Solve" onclick="solve()"> </form> Notice that the onclick runs solve. Let's look at that: function solve() { console.log('running...'); ColdFusion.Ajax.submitForm('myform','test.cfm',resultHandler); console.log('done...'); } First and foremost - look at my use of console.log. You need to stop using Alert. I know it's easy. But Alert can be a real pain in the you know what. Download Firebug and get used to doing your debugging there. Ok, so in between two debug statements I'm running a submitForm action. I've said to submit myform to test.cfm and then run resultHandler. I made test.cfm simply cfoutput a random number for testing purposes. The first thing I ran into was that ColdFusion.Ajax.submitForm didn't exist. Remember that ColdFusion only loads the Ajax functionality it thinks it needed. Since I didn't really use any ColdFusion tags, it didn't load squat. The trick to handle this was discovered by Todd Sharp, just add this to the top of your page: <cfajaximport /> Ok, so now I can run my application and see the request, how do we handle it, and why is he getting a large alert? First look at a more full test.cfm: <cfparam name="form.number1" default="0"> <cfparam name="form.number2" default="0"> <cfset form.number1 = val(form.number1)> <cfset form.number2 = val(form.number2)> <cfoutput>#form.number1+form.number2#</cfoutput> (And by the way, I should be more anal with my URL checks in this code.) Now let's look at resultHandler: function resultHandler(result) { console.log('result handler ran...'); console.log(result); } When I ran my test, I noticed that result was indeed a large string with a lot of white space. That could be what you are seeing in the large alert. The white space is simply a result of ColdFusion liking whitespace like a Lohan needs publicity. We can fix this a few ways. We can reduce the whitespace in the CFM with a simple CFSETTING. But that's kinda boring. When I saw this on ColdFusionBloggers</a. a few minutes ago I thought it was perfect timing: Cranky Bit: Trimming a String in JavaScript I added his code (note his regex is missing a \ in front of each s) and ended up with this: <script> String.prototype.trim = function() { return this.replace(/^\s+|\s+$/g,""); } function resultHandler(result) { console.log('result handler ran...'); console.log(result.trim()); } function solve() { console.log('running...'); ColdFusion.Ajax.submitForm('myform','test.cfm',resultHandler); console.log('done...'); } </script> Now when I ran the code I got a nicely trimmed response. I added one more line to set the result value: document.getElementById("result").value = result.trim();

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