Regex for alphanumeric password, with at least 1 number and character

Question

Need help with a regex for alphanumeric password, with at least 1 number and character, and the length must be between 8-20 characters.

I have this but doesn\'t seem

Answer 1

This code is for javascript

// *********** ALPHA-Numeric check ***************************
function checkAlphaNumeric(val)
{
    var mystring=new String(val)

    if(mystring.search(/[0-9]+/)==-1) // Check at-leat one number
    {
        return false;
    }
    if(mystring.search(/[A-Z]+/)==-1 && mystring.search(/[a-z]+/)==-1) // Check at-leat one character
    {
        return false;
    }
}