Jquery RegEx Validation

Question

I am wanting to check if an input field has the attribute "pattern" and if so, preform a regex check aganst said pattern.I know this is already done by HTML5, but I am wanting to handle the event myself. I am receiving this error: Uncaught TypeError: Object a-zA-Z has no method 'test'

 ///Check Perform Reg///////////////////////////////////////////////////////
         if ($(this).attr("pattern")) {
             var reg = $(this).attr("pattern");
             var currentValue = $(this).val();


             if (reg.test(currentValue)) {
                 $(this).after($error.clone().text("Invalid Input.Try Again."));
                 $(".error:hidden").fadeIn("slow");
                 hasError = true;
                 return false;
             }

             }
        ///////////////////////////////////////////////////////////////////////////

Still no luck,

also here is my html:

<div>
    <input class="formInput" name="First Name" pattern="^[A-Za-z_-][A-Za-z0-9_-]*$" type="text"  id="frmFirst" min="2" maxlength="30"  required="required"/>
    <span>First Name</span>
</div>

This is not a good solution set the pattern in the HTML part because anyone can bypass that without any check. So, you should to check if the pattern match directly in the js. — Marco Concas
– Marco Concas, Commented Sep 30, 2019 at 16:42

irfanmcsd · Accepted Answer · 2012-04-06 04:03:29Z

28

Normally regular expression with javascript / jquery handle like

var reg = /pattern/;
if (reg.test($(this).val())) {
    // perform some task
}

answered Apr 6, 2012 at 4:03

irfanmcsd

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2 Comments

user1265533 Over a year ago

It appears to be the same thing my code already does. except the pattern is passed from a variabel

irfanmcsd Over a year ago

yea it look like same, for regular expression you need to enclose pattern within /[pattern]/ e.g /test/ for matching with value test.

deezy · Accepted Answer · 2013-04-17 07:39:38Z

As already mentioned by others you need to use an object instead of the string returned by the jQuery attr() method. You can see the difference between the two here.

Will return "string":

var reg = $(this).attr("pattern");
console.log(typeof reg)

Will return with "object":

var reg = new RegExp($(this).attr("pattern"));
console.log(typeof reg);

So if you replace:

var reg = $(this).attr("pattern");

With:

var reg = new RegExp($(this).attr("pattern"));

The Uncaught TypeError: Object a-zA-Z has no method 'test' error will disappear

...but your validation still won't work very well. Your conditional logic says if the regex test returns TRUE then handle an error:

if (reg.test(currentValue)) {
    //error handling
}

Instead it should handle an error if the test returns FALSE:

if (!reg.test(currentValue)) {
    //error handling
}

This should work for you.

rrtx2000 · Accepted Answer · 2013-04-26 16:11:06Z

5

You can try something like this. It will alert "var2 failed".

var var1 = "1";
var var2 = "A";
var myRegEx = new RegExp('[0-9]+'); //make sure the var is a number

if (var1 != myRegEx.exec(var1)) {
    alert("var1 failed");
}

if (var2 != myRegEx.exec(var2)) {
    alert("var2 failed");
}

answered Apr 26, 2013 at 16:11

rrtx2000

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Comments

Qtax · Accepted Answer · 2012-04-06 04:17:59Z

0

A string is not a RegExp object. You could use something like:

var reg = new RegExp($(this).attr("pattern"));

answered Apr 6, 2012 at 4:17

Qtax

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Comments

Qasim Bataineh · Accepted Answer · 2015-12-22 19:07:48Z

0

Below is the proper way to validate a text-box based on a regular Expression using Jquery in MVC. Please note that this expression is made to validate multi email addresses in one string:

      var emailReg = new RegExp(/^([A-Z0-9.%+-]+@@[A-Z0-9.-]+.[A-Z]{2,6})*([,;][\s]*([A-Z0-9.%+-]+@@[A-Z0-9.-]+.[A-Z]{2,6}))*$/i);
      var emailText = $('#email').val();

      if (!emailReg.test(emailText)) {
          alert('Wrong Email Address\Addresses format! Please reEnter correct format');
            return false;
        }
    }

answered Dec 22, 2015 at 19:07

Qasim Bataineh

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1 Comment

Qasim Bataineh Over a year ago

Jquery is the same anywhere. You just need to apply it to a text-box or input field where you like to validate against this jquery expression.

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