Text box validation check

Question

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How to display alert message if text box starts with <? or <! or text contains like <text> using java script or jquery.

What I have tried:

Tried using regular expression but its not working properly.

Posted 4-Apr-16 19:40pm

Rakesh Tripathy

Updated 4-Apr-16 20:02pm

v4

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Comments

Abhipal Singh 5-Apr-16 1:43am

What does that "" mean.. empty textbox? or a space. Also share the regex that is failing to validate.

Rakesh Tripathy 5-Apr-16 1:59am

if text box starts with <? or <! or text contains like <text>

Karthik_Mahalingam 5-Apr-16 1:50am

you mean two double quotes ""??

Rakesh Tripathy 5-Apr-16 1:55am

if text box starts with <? or <! or text contains like <text>

Rakesh Tripathy 5-Apr-16 2:20am

how to check for a text contains contains like <text>

Karthik_Mahalingam 5-Apr-16 2:25am

itemsToValidate.push('<text>');
add this in the below code.

Rakesh Tripathy 5-Apr-16 2:28am

Here text means textbox value e.g: <hello>

Karthik_Mahalingam 5-Apr-16 2:29am

startswith right?

Rakesh Tripathy 5-Apr-16 2:34am

if contains textbox value inside <> for e.g: <hello>

Karthik_Mahalingam 5-Apr-16 2:36am

itemsToValidate.push('<hello>');

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Karthik_Mahalingam · Answer 1 · 2016-04-04T20:02:00

Solution 1

Try this

HTML

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>

    <script>
        function validateFun() {
            debugger;
            var txt = document.getElementById('txt1');
            var value = txt.value.trim();
            var itemsToValidate = [];
            itemsToValidate.push('<&');
            itemsToValidate.push('<!');
            for (var i = 0; i < itemsToValidate.length; i++) {
                if (value.startsWith(itemsToValidate[i])) {
                    alert('Your message');
                    return false;
                }
            }

            return true;
        }

    </script>
</head>
<body>

    <input type="text" id="txt1" value=" " />
    <button onclick="return validateFun();">sub</button>

</body>



</html>

Posted 4-Apr-16 20:02pm

Karthik_Mahalingam

Comments

Rakesh Tripathy 5-Apr-16 2:24am

but how to check for a text contains like <text>

Karthik_Mahalingam 5-Apr-16 2:32am

starts with ?

Karthik_Mahalingam 5-Apr-16 2:32am

add this line itemsToValidate.push('<text>');

Rakesh Tripathy 5-Apr-16 2:37am

if user will input value in text box startwith < and endswith > for e.g: <hello world>

Karthik_Mahalingam 5-Apr-16 2:46am

give some examples, i cant get it

Rakesh Tripathy 5-Apr-16 2:52am

if user will input value in text box startwith < and endswith > for e.g: <hello world>

Karthik_Mahalingam 5-Apr-16 3:53am

so you mean, start with and ends with validation?
Please be very clear while asking query.

Karthik_Mahalingam 5-Apr-16 3:56am

try this code..

function validateFun() {
debugger;
var txt = document.getElementById('txt1');
var value = txt.value.trim();
var itemsToValidate = [];
itemsToValidate.push('<&');
itemsToValidate.push('<!');
for (var i = 0; i < itemsToValidate.length; i++) {
if (value.startsWith(itemsToValidate[i])) {
alert('Your message');
return false;
}
}
if( value.startsWith('<') && value.endsWith('>') )
{
alert('it starts with < and ends with >');
return false;
}

return true;
}

Rakesh Tripathy 5-Apr-16 22:46pm

Thank you Karthik.

Karthik_Mahalingam 5-Apr-16 23:27pm

if it works, could you please close this post, by marking it as answer. so that no one will post further answers.