Write bangla Unicode in bijoy rule without installing bijoy software

// Set of Characters
var textarea_bn; //active text area
var unijoy = new Array();


// the word those are use pre-character
var rashed_swap_array = new Array();
rashed_swap_array[0] = 'c'; // e kar
rashed_swap_array[1] = 'C'; //Oi Kar
rashed_swap_array[2] = 'd'; // hrossho i kar


// the word those are use before-character
var hr_post_array = new Array();
hr_post_array[0] = 'f'; // e kar
hr_post_array[1] = 'D'; //Oi Kar
hr_post_array[2] = 'X'; // hrossho i kar
hr_post_array[3] = 'Z'; // hrossho i kar

// the words which are not character

var hr_not_character = new Array();

hr_not_character[0] = 'c'; // e kar
hr_not_character[1] = 'C'; //Oi Kar
hr_not_character[2] = 'd'; // hrossho i kar
hr_not_character[3] = 'f'; // e kar
hr_not_character[4] = 'D'; //Oi Kar
hr_not_character[5] = 'X'; // hrossho i kar
hr_not_character[6] = 'Z'; // hrossho i kar




// unijoy bangla equivalents
unijoy['j'] = "\u0995"; // ko

unijoy['d'] = '\u09BF'; // hrossho i kar
unijoy['gd'] = '\u0987'; // hrossho i
unijoy['D'] = '\u09C0'; // dirgho i kar
unijoy['gD'] = '\u0988'; // dirgho i
unijoy['c'] = '\u09C7'; // e kar
unijoy['gc'] = '\u098F'; // E
unijoy['gs'] = '\u0989'; // hrossho u
unijoy['s'] = '\u09C1'; // hrossho u kar
unijoy['S'] = '\u09C2'; // dirgho u kar
unijoy['gS'] = '\u098A'; // dirgho u
unijoy['v'] = '\u09B0'; // ro
unijoy['a'] = '\u098B'; // wri
unijoy['f'] = '\u09BE'; // a kar
unijoy['gf'] = '\u0986'; //shore a
unijoy['F'] = '\u0985'; // shore ao
//unijoy['ao']='\u0985'; // shore o
unijoy['n'] = '\u09B8'; // dontyo so
unijoy['t'] = '\u099f'; // to
unijoy['J'] = '\u0996'; // Kho

//unijoy['kh'] = '\u0996'; // kho

unijoy['b'] = '\u09A8'; // dontyo no
unijoy['B'] = '\u09A3'; // murdhonyo no
unijoy['k'] = '\u09A4'; // tto
unijoy['K'] = '\u09A5'; // ttho

unijoy['e'] = '\u09A1'; // ddo
unijoy['E'] = '\u09A2'; // ddho

unijoy['h'] = '\u09AC'; // bo
unijoy['H'] = '\u09AD'; // bho
//unijoy['v']='\u09AD'; // bho
//unijoy['rh']='o';	 // doye bindu ro
unijoy['p'] = '\u09DC';  // doye bindu ro
unijoy['P'] = '\u09DD';  // dhoye bindu ro
unijoy['o'] = '\u0997'; // go
unijoy['O'] = '\u0998'; // gho

//unijoy['gh']='\u0998'; // gho

unijoy['i'] = '\u09B9'; // ho
unijoy['I'] = '\u099E'; // yo
unijoy['u'] = '\u099C'; // borgio jo
unijoy['U'] = '\u099D'; // jho
//unijoy['jh']='\u099D'; // jho
unijoy['y'] = '\u099A'; //  cho
unijoy['Y'] = '\u099B'; // cho
//unijoy['C']='\u099B'; // ccho
unijoy['T'] = '\u09A0'; // tho
unijoy['r'] = '\u09AA'; // po
unijoy['R'] = '\u09AB'; // fo
//unijoy['ph']='\u09AB'; // fo
unijoy['l'] = '\u09A6'; // do
unijoy['L'] = '\u09A7'; // dho

unijoy['w'] = '\u09AF'; // ontoshyo zo
unijoy['W'] = '\u09DF'; // ontostho yo
unijoy['q'] = '\u0999'; // Uma
unijoy['Q'] = '\u0982'; // uniswor
unijoy['V'] = '\u09B2'; // lo
unijoy['m'] = '\u09AE'; // mo
unijoy['M'] = '\u09B6'; // talobyo sho
unijoy['N'] = '\u09B7'; // mordhonyo sho
unijoy['gx'] = '\u0993'; //'\u09CB'; // o
unijoy['X'] = '\u09CC'; // ou kar
unijoy['gX'] = '\u0994'; // OU
//unijoy['Ou']='\u0994'; // OU
unijoy['gC'] = '\u0990'; // Oi
//unijoy['\\']='\u09CE'; // tto
//unijoy['|']='\u0983'; // bisworgo
unijoy["G"] = "\u0964"; // dari
//unijoy[".."] = "."; // fullstop

//unijoy['g'] = ' '; //'\u09CD' + '\u200c'; // hosonto
unijoy['g'] = '\u09CD'; //change by rashed


unijoy['&'] = '\u0981'; // chondrobindu
unijoy['Z'] = '\u09CD' + '\u09AF'; // jo fola
unijoy['gh'] = '\u09CD' + '\u09AC'; // bo fola
unijoy['ga'] = '\u098B'; // wri kar
unijoy['a'] = '\u09C3'; // wri 
//unijoy['k'] ="\u0995"  + '\u09CD'+ '\u09B8';
unijoy['rZ'] = unijoy['r'] + '\u200c' + '\u09CD' + '\u09AF';
unijoy['z'] = '\u09CD' + unijoy['v'];
unijoy['x'] = '\u09CB';
unijoy['C'] = '\u09C8'; //Oi Kar
unijoy['\\'] = '\u0983';
unijoy['|'] = '\u09CE'; // bisworgo




var carry = '';  //This variable stores each keystrokes
var carry_rashed = '';
var old_len = 0; //This stores length parsed bangla charcter
var ctrlPressed = false;
var first_letter = false;
var lastInserted;

isIE = document.all ? 1 : 0;
var switched = false;

function checkKeyDown(ev) {
    //just track the control key
    var e = (window.event) ? event.keyCode : ev.which;
    if (e == '17') {
        ctrlPressed = true;
    }
}

function checkKeyUp(ev) {
    //just track the control key
    var e = (window.event) ? event.keyCode : ev.which;

    if (e == '17') {
        ctrlPressed = false;
        //alert(ctrlPressed);
    }

}



function parseunijoy(evnt, textarea_bn) {
    // main unijoy parser
   
    //var t = document.getElementById(textarea_bn); // the active text area
    var t=textarea_bn;
     var myField;
     myField=t;
    var e = (window.event) ? event.keyCode : evnt.which; // get the keycode
  
    if (e == '113') {
        //switch the keyboard mode
        if (ctrlPressed) {
            switched = !switched;
            //alert("H"+switched);
            return true;
        }
    }

    if (switched) return true;

    if (ctrlPressed) {
        // user is pressing control, so leave the parsing
        e = 0;
    }

    var char_e = String.fromCharCode(e); // get the character equivalent to this keycode

    if (e == 8 || e == 32) {
        // if space is pressed we have to clear the carry. otherwise there will be some malformed conjunctions
        carry = " ";
        old_len = 1;
        return;
    }

    lastcarry = carry;
    carry += "" + char_e;  //append the current character pressed to the carry
    carry_rashed = carry;


    bangla = parseunijoyCarry(carry); // get the combined equivalent
    tempBangla = parseunijoyCarry(char_e); // get the single equivalent

    if (tempBangla == ".." || bangla == "..") //that means it has sibling
    {

        return false;
    }
    if (char_e == "g") {
        if (carry == "gg") {
            // check if it is a plus sign
            insertConjunction('\u09CD' + '\u200c', old_len);
            old_len = 1;
            return false;
        }
        //otherwise this is a simple joiner
      
        insertAtCursor("\u09CD",t); old_len = 1;
        carry = "g";
        return false;
    }

    else if (old_len == 0) //first character
    {

        // this is first time someone press a character
        insertConjunction(bangla, 1,t);
        old_len = 1;

        return false;

    }
    
    else if (char_e == "A") {
        //process old style ref
        //	    if (Check_Post_Character_Exist(get_unicode_to_character_rashed(lastInserted)) == 1) {

        newChar = unijoy['v'] + '\u09CD' + lastInserted;
       // var myField = document.getElementById('textarea_bn');
        var value_field = "";

        var startPos = myField.selectionStart;

        var last_fifth_one = myField.value.substring(startPos - 5, startPos - 4);
        var last_forth_one = myField.value.substring(startPos - 4, startPos - 3);
        var last_third_one = myField.value.substring(startPos - 3, startPos - 2);
        var last_second_one = myField.value.substring(startPos - 2, startPos - 1);
        var last_one = myField.value.substring(startPos - 1, startPos);


        //
        // if character[last] is character: gorto, 
        //
        if (Check_Character_Exist_orNot(get_unicode_to_character_rashed(last_one)) == 0) {

            // if last previous one is g then "ref" add with (g-1) located character
            if (get_unicode_to_character_rashed(last_second_one) == 'g') {
                newChar = unijoy['v'] + '\u09CD' + last_third_one + last_second_one + last_one;
                myField.value = myField.value.substring(0, startPos - 4) + myField.value.substring(startPos - 4, startPos - 3) + newChar;
            }
            else {
                newChar = unijoy['v'] + '\u09CD' + last_one;
                myField.value = myField.value.substring(0, startPos - 2) + myField.value.substring(startPos - 2, startPos - 1) + newChar;
            }
        }
        else {
            // if last previous one is g then "ref" add with (g-1) located character: kargo
//            alert(last_forth_one + ' ' + last_third_one + ' ' + last_second_one + ' ' + last_one);

            if (Check_Character_Exist_orNot(get_unicode_to_character_rashed(last_second_one)) == 1) {
                if (get_unicode_to_character_rashed(last_forth_one) == 'g') {
                    newChar = unijoy['v'] + '\u09CD'+ last_fifth_one+ last_forth_one + last_third_one + last_second_one + last_one;
                    myField.value = myField.value.substring(0, startPos - 6) + myField.value.substring(startPos - 6, startPos - 5) + newChar;
                  
                }
                else {
                    newChar = unijoy['v'] + '\u09CD' + last_third_one + last_second_one + last_one;
                    myField.value = myField.value.substring(0, startPos - 4) + myField.value.substring(startPos - 4, startPos - 3) + newChar;
                }
            }
            else {
                // alert(last_forth_one + ' ' + last_third_one + ' ' + last_second_one + ' ' + last_one);
                //example: gorde
                if (get_unicode_to_character_rashed(last_third_one) == 'g') {
                    newChar = unijoy['v'] + '\u09CD'+last_forth_one + last_third_one + last_second_one + last_one;
                    myField.value = myField.value.substring(0, startPos - 5) + myField.value.substring(startPos - 5, startPos - 4) + newChar;
                }
                else {
                    newChar = unijoy['v'] + '\u09CD' + last_second_one + last_one;
                    myField.value = myField.value.substring(0, startPos - 3) + myField.value.substring(startPos - 3, startPos - 2) + newChar;
                }
            }

        }
       
        return false;
    }


    else if ((bangla == "" && tempBangla != "")) //that means it has no joint equivalent
    {
        // there is no joint equivalent - so show the single equivalent. 
        bangla = tempBangla;
        if (bangla == "") {
            // there is no available equivalent - leave as is
            carry = "";
            return;
        }

        else {
            // found one equivalent

            carry = char_e;
            insertAtCursor(bangla,t);
            old_len = bangla.length;
            return false;
        }
    }
    else if (bangla != "")//joint equivalent found 
    {
        // we have found some joint equivalent process it
       
        insertConjunction(bangla, old_len);
        old_len = bangla.length;
        return false;
    }

   

}

function parseunijoyCarry(code) {
    //this function just returns a bangla equivalent for a given keystroke
    //or a conjunction
    //just read the array - if found then return the bangla eq.
    //otherwise return a null value
    if (!unijoy[code])  //Oh my god :-( no bangla equivalent for this keystroke
    {
        return ''; //return a null value
    }
    else {
        return (unijoy[code]);  //voila - we've found bangla equivalent
    }

}

function get_unicode_to_character_rashed(param_unicode) {

    for (keyVar in unijoy) {
        if (unijoy[keyVar] == param_unicode) {
            return keyVar;
        }

    }
    return '';

}

//----------------------------------------------Check the bangla pre-vowel-------
function Check_Pre_Character_Exist(p_char) {

    var tag_found = 0;
    for (var p_char_index = 0; p_char_index < rashed_swap_array.length; p_char_index++) {

        if (rashed_swap_array[p_char_index].toString() == p_char) {
            tag_found = 1;
            return tag_found;
        }
    }
    return tag_found;
}
//-----------------------------------------------------------------------------------


//----------------------------------------------Check the bangla post-character-------
function Check_Post_Character_Exist(p_char) {

    var tag_found = 0;
    for (var p_char_index = 0; p_char_index < hr_post_array.length; p_char_index++) {

        if (hr_post_array[p_char_index].toString() == p_char) {
            tag_found = 1;
            return tag_found;
        }
    }
    return tag_found;
}
//-----------------------------------------------------------------------------------

//----------------------------------------------Check the bangla post-character-------
function Check_Character_Exist_orNot(p_char) {

    var tag_found = 0;
    for (var p_char_index = 0; p_char_index < hr_not_character.length; p_char_index++) {

        if (hr_not_character[p_char_index].toString() == p_char) {
            tag_found = 1;
            return tag_found;
        }
    }
    return tag_found;
}
//-----------------------------------------------------------------------------------


function insertAtCursor(myValue,myField) {
    /**
    * this function inserts a character at the current cursor position in a text area
    * many thanks to alex king and phpMyAdmin for this cool function
    * 
    * This function is originally found in phpMyAdmin package and modified by Hasin Hayder to meet the requirement
    */
  
    lastInserted = myValue;
    //var myField = document.getElementById('textarea_bn');
  
    if (document.selection) {
        //alert("hello2");
        myField.focus();
        sel = document.selection.createRange();

        sel.text = myValue;

        sel.collapse(true);
        sel.select();
    }
    //MOZILLA/NETSCAPE support
    else if (myField.selectionStart || myField.selectionStart == 0) {
        
        var startPos = myField.selectionStart;
        var endPos = myField.selectionEnd;
        var scrollTop = myField.scrollTop;
        startPos = (startPos == -1 ? myField.value.length : startPos);

        //alert(myField.value.substring(startPos - 1, startPos));

       

        // rashed
        if (Check_Pre_Character_Exist(get_unicode_to_character_rashed(myValue)) == 1) {
            // if user change the cursor and give e-kar in front of any character then
            if (myField.value.substring(startPos, startPos + 1) == ' '
                || myField.value.substring(startPos, startPos + 1) == '') {

              
                myField.value = myField.value.substring(0, startPos)
                        + '`'
                        + myValue
		                + myField.value.substring(endPos, myField.value.length);
            }
            else {
                myField.value = myField.value.substring(0, startPos + 1)
                    + myValue
                    + myField.value.substring(startPos + 1);
            }
        }
        else if (Check_Pre_Character_Exist(carry_rashed.substring(0, 1))) {

      
            if (myField.value.substring(startPos - 2, startPos - 1) == '`') {

                myField.value = myField.value.substring(0, startPos - 2)
                    + myValue
                    + myField.value.substring(startPos - 1, startPos)
                    + myField.value.substring(endPos, myField.value.length);
            }
            else {
                myField.value = myField.value.substring(0, startPos - 1)
                + myValue
                + myField.value.substring(startPos - 1, startPos)
		        + myField.value.substring(endPos, myField.value.length);
            }
        }
        else {
            //
            // if any body write like dhoy-dho then it will work
            //

            //		    if (carry_rashed.substring(0, 1) != ' '){
            if (myField.value.substring(startPos - 1, startPos) != ' ') {
                if (carry_rashed.substring(1, 2) == 'g') {
                    myField.value = myField.value.substring(0, startPos)
		            + myValue
		            + myField.value.substring(endPos, myField.value.length);
                }
                else {

                    if (carry_rashed.substring(0, 1) == 'g') {
                        if (Check_Pre_Character_Exist(get_unicode_to_character_rashed(myField.value.substring(startPos - 2, startPos - 1))) == 1) {
                            myField.value = myField.value.substring(0, startPos - 2)
		                + myField.value.substring(startPos - 1, startPos)
                        + myValue
		                + myField.value.substring(startPos - 2, startPos - 1)
		                + myField.value.substring(endPos, myField.value.length);
                        }
                        else {
                            myField.value = myField.value.substring(0, startPos)
		                    + myValue
		                    + myField.value.substring(endPos, myField.value.length);
                        }
                    }
                    else {
                        myField.value = myField.value.substring(0, startPos)
		                    + myValue
		                    + myField.value.substring(endPos, myField.value.length);
                    }

                }

            }
            else {
                myField.value = myField.value.substring(0, startPos)
		            + myValue
		            + myField.value.substring(endPos, myField.value.length);
            }

        }


      

        myField.focus();
        myField.selectionStart = startPos+1 + myValue.length;
        myField.selectionEnd = startPos+1 + myValue.length;
        myField.scrollTop = scrollTop;
       

    } else {
        var scrollTop = myField.scrollTop;
        myField.value += myValue;
        myField.focus();
        myField.scrollTop = scrollTop;
    }
}

function insertConjunction(myValue, len, myField) {
    /**
    * this function inserts a conjunction and removes previous single character at the current cursor position in a text area
    * 
    * This function is derived from the original one found in phpMyAdmin package and modified by Hasin to meet our need
    */

    lastInserted = myValue;
   
    //var myField = document.getElementById(textarea_bn);
    //alert(myField)
    if (document.selection) {
        myField.focus();
        sel = document.selection.createRange();
        if (myField.value.length >= len) {  // here is that first conjunction bug in IE, if you use the > operator
            sel.moveStart('character', -1 * (len));
            //sel.moveEnd('character',-1*(len-1));
        }
        sel.text = myValue;
        sel.collapse(true);
        sel.select();
    }
    //MOZILLA/NETSCAPE support
    else if (myField.selectionStart || myField.selectionStart == 0) {
        myField.focus();
        var startPos = myField.selectionStart - len;
        var endPos = myField.selectionEnd;
        var scrollTop = myField.scrollTop;
        startPos = (startPos == -1 ? myField.value.length : startPos);

        if (Check_Pre_Character_Exist(get_unicode_to_character_rashed(myField.value.substring(startPos, endPos))) == 1) {
            myField.value = myField.value.substring(0, startPos - 1)
            + myValue
            + myField.value.substring(startPos, endPos)
		    + myField.value.substring(endPos, myField.value.length);
        }
        else {
            myField.value = myField.value.substring(0, startPos)
		            + myValue
		            + myField.value.substring(endPos, myField.value.length);
        }



        myField.focus();
        myField.selectionStart = startPos + myValue.length;
        myField.selectionEnd = startPos + myValue.length;
        myField.scrollTop = scrollTop;
    } else {
        var scrollTop = myField.scrollTop;
        myField.value += myValue;
        myField.focus();
        myField.scrollTop = scrollTop;
    }

   

    //document.getElementById("len").innerHTML = len;
}