Validate the text with JavaScript/jQuery

Question

while typing in an input, I want to validate the text character by character e.g text is: The Quick Brown Fox

I want to match character by character

like: initially, text box in empty:

I press

T => OK

h => OK

a => Not Ok (will not be written in the text)

e => OK

and so on

I've written this jquery regex expression. But, it's not working as it is comparing the whole text.

$("#text").on("keypress", function(e) {
    if (!(/^The Quick Brown Fox$/i.test($(this).val()+String.fromCharCode(e.keyCode)))) {
        return false;
    }
}

You are checking for each key press while your regex matches for the entire string. Check once the entire string has been entered. — Aashray
– Aashray, Commented May 5, 2014 at 6:14
You are specifically prepending the entire string ($(this).val()+) when you test. — PhistucK
– PhistucK, Commented May 5, 2014 at 6:16
Why not lookupString.indexOf($(this).val()) !== -1 instead? — PhistucK
– PhistucK, Commented May 5, 2014 at 6:19

Mithun Satheesh · Accepted Answer · 2014-05-05 06:24:50Z

2

you can try it like

$("#text").on("keypress", function(e) {

    var myText = ($(this).val()+String.fromCharCode(e.keyCode));

    if ('The Quick Brown Fox'.indexOf(myText) != 0) {
        return false;
    }

});

Here is a sample fiddle.

answered May 5, 2014 at 6:24

Mithun Satheesh

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Comments

Jeremy J Starcher · Accepted Answer · 2014-05-05 06:15:51Z

1

The regex isn't the best choice for doing this kind of thing.

You'll be better off setting up a string and looping through characters, one-by-one until you find a mismatch.

Check the string, from the beginning, each time a key is hit. That catches people pasting into the input.

answered May 5, 2014 at 6:15

Jeremy J Starcher

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Aashray · Accepted Answer · 2014-05-05 06:16:29Z

0

You are checking for each key press while your regex matches for the entire string. Check once the entire string has been entered.

$("#text").on("blur", function(e) {
    if (!(/^The Quick Brown Fox$/i.test($(this).val()))) {
        return false;
    }
}

answered May 5, 2014 at 6:16

Aashray

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1 Comment

Muaaz Khalid Over a year ago

But, I want to check while typing.. not after typing.

dreamweiver · Accepted Answer · 2014-05-05 07:04:52Z

0

May be you can loop and compare character by character and do the processing.

HTML: Enter the Proper text:

JQUERY CODE:

    var txt = "The Quick Brown Fox";
    var index = 0;
    $("#text").on("keyup", function (e) {
          var st = $('#text').val();
          while (index < st.length) {
              if (txt[index] === st[index]) index++;
              else {
                  $(this).val(st.substr(0, index));
                  break;
              }
          }
    });

LIVE DEMO: http://jsfiddle.net/dreamweiver/2dadL/21/

Happy Coding :)

answered May 5, 2014 at 7:04

dreamweiver

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