JS function to check whether the given string contains only Alphanumeric characters - Javascript String functions

Javascript ( JS ) function to check whether the given string contains only Alphanumeric characters.

Simple JS function to check whether the string contains either only Numbers, Capital or Small Letter alphabets or a combination of all.






Function Explained

input_string is the input to the function

Pattern /^[0-9a-zA-Z]+$/ is a regular expression which allows only Numbers (0 to 9), Capital Letter Alphabets ( A to Z ) , Small Letter Alphabets ( a to z )

Function match the input string with the regular expression and if a match is found, it return boolean TRUE else return FALSE.

function isAlphanumeric(input_string)
{
// This function checks whether the given string contains Alphanumeric characters only

var check_pattern = /^[0-9a-zA-Z]+$/;
if(input_string.match(check_pattern))
return true;
else
return false;
}

How to use this JS function?

if( isAlphanumeric("YOUR_STRING_TO_CHECK") ){
alert("Yes Dude, Your string is Alphanumeric :)");
}else{
alert("Sorry, Your string is not an alphanumeric one :(");
}

Following examples return TRUE as output

isAlphanumeric("ABCD")
isAlphanumeric("2345")
isAlphanumeric("AB45")
isAlphanumeric("23CD")

Following examples return FALSE as output

isAlphanumeric(" ")
isAlphanumeric("%$@%$@")
isAlphanumeric("AS98%#%%")
isAlphanumeric("CD*^*")
isAlphanumeric("234*%*")

Full Code

<script>

function isAlphanumeric(input_string)
{
// This function checks whether the given string contains Alphanumeric characters only

var check_pattern = /^[0-9a-zA-Z]+$/;
if(input_string.match(check_pattern))
return true;
else
return false;
}

if( isAlphanumeric("23AS2#$") ){
alert("Yes Dude, Your string is Alphanumeric :)");
}else{
alert("Sorry, Your string is not an alphanumeric one :(");
}

</script>

Hope this helps :) share and post your feedbacks:)