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This piece of code will separate out the account number and routing number from a scanned check. I yanked this function out of a payment class I wrote for a point of sale web application I recently developed. It’s a mootools class, but the core logic can be pulled out and applied pretty much anywhere.

1. First pass a string into the function, where the string is the string from the check scan
2. I immediately validate the information is correct. Scanners will send a series of question marks if the check was scanned in at an odd angle. They are very picky, but I tested many ways of sending the check through and this should catch most scenarios
3. The routing number is stored between two “T” characters in the string. So I look for the T’s, remove them and store off the routing number
4. The end of the accounting number has a “U” character immediately after it so and the account number starts immediately after the routing number, so I substring that out
5. I then do some more error checking. Since both the account and routing number should be numeric I use isNan() to verify this.
6. The entire snippet is wrapped in a try catch so should anything fail it can be logged and reported to the end user

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	setCheckAttributes: function(string){
		try{
			if(string.charAt(0)=='?' || string.charAt(1)=='?' || string.charAt(1)=='?')
			{
				displayMessageWindow('Invalid Check','Please verify the check was scanned properly with the check facing in and the routing/account numers at the bottom','error');
				return false;
			}
 
			var t1=string.search("T"); // start of routing number indentifier
			string = string.replace("T","");
			var t2=string.search("T"); // end of routing number indentifier, start of account number indentifier
 
			this.routing = string.substring(t1,t2); // set routing number
 
			var u=string.lastIndexOf("U"); // end of account number indentifier
 
			var account = string.substring((t2+1),u);
			var accountArr = account.split(" ");
 
			this.account = accountArr.join(""); // set account number
 
			if(isNaN(this.account) || isNaN(this.routing)){
				this.account='';
				this.routing='';
				this.payment_method_id=0;
				this.type='';
				displayMessageWindow('Invalid Check','The system encountered an error reading the check and has invalid (non-numeric) information for either the routing or account number.','error');
				return false;
			}
			return true;
		}
		catch(err){
			 pushToErrorLog('class Payment::setCheckAttributes() ' + err);
			 return false;
		}

To determine when a check has been scanned you can use the code in my post, JavaScript snippet for handling credit card readers.

This entry was posted on Friday, October 17th, 2008 at 5:57 pm and is filed under ajax/dom/javascript. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.