Latitude Longitude Validation using Javascript in .net

Question

I have two textbox one for latitude and other for longtitude.
following is the regex i am using
for latitude /^(\+|-)?(?:90(?:(?:\.0{1,7})?)|(?:[0-9]|[1-8][0-9])(?:(?:\.[0-9]{1,7})?))$/g
and for longitude /^(\+|-)?(?:180(?:(?:\.0{1,7})?)|(?:[0-9]|[1-9][0-9]|1[0-7][0-9])(?:(?:\.[0-9]{1,7})?))$/g
There is submit button,when user enter latitude and longitude and clicks submit button,we compare latitude and longitude base on regex,if it is invalida do not allow user to proceed further. but instead of button click i have to do it on textbox keypress,while entering he will not be allowed to enter latitude and longitude which does not matches the regex,please lete me know how this could be done on textbox keypress

Jignesh Kumar · Answer

Hi Aniket,   You can use keypress event for both text input and create Jquery function for that as below, $(document).ready( function (){       $( '#longitude' ).keypress( function (e) {           let pattern =  new  RegExp( '^-?([1-8]?[1-9]|[1-9]0)\.{1}\d{1,6}' );           return  pattern.test( this .value));       });               $( '#latitude' ).keypress( function (e) {           let pattern =  new  RegExp( '^-?([1-8]?[1-9]|[1-9]0)\.{1}\d{1,6}' );           return  pattern.test( this .value));       });   })

Sachin Singh · Answer

You can't validate on keypress, keypress means if they enter 1 then it will validate again if they enter 2 then it will validate 12 and so on. so instead on keypress validate on focus lost. so after inserting both lat and long when they move from long textbox to some other form's input at that time it should fire. function validateLatLng(lat, lng) {         let pattern = new RegExp( '^-?([1-8]?[1-9]|[1-9]0)\.{1}\d{1,6}' );          return pattern.test(lat) && pattern.test(lng);   }      $( "#long" ).blur(function()   {   validateLatLng($( "#lat" ).val(),$( "#long" ).val());   });

Nitin Sontakke · Answer

Please correct me if I am wrong here, but I believe the lat long values are just decimal values. I do agree in principle that you may expect them to be within a specific range.   For such a simple validation, I personally think that this is a bit of overkill. If you are targetting html5 compliant browsers, can you not use numeric input, just a thought.   Validating input programatically on keypress is a complex process (may be it is just me), as you will also need to cater to other key press values such as Escape, left arrow, right arrow, etc. I believe, if you are using just text input, why not just use parseFloat just before submit and alert the user.