javascript - Get key char (value) from keycode with shift modifier - Stack Overflow

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I have been lucky to find String.fromCharCode(). It has helped me significantly. However, I noticed it doesn't take into account the shift modifier. I know the event.shiftKey property and use it, but right now I need to get the key value (eg: "A" or "a") which takes into account the shift key modifier. At first I used String.toLowerCase().. But I neglected to think of number keys, to give one example: "5" (without shift) and "%" (with shift). I need to differentiate between the two in my program. What's an easy way to get the key char value?

I have been lucky to find String.fromCharCode(). It has helped me significantly. However, I noticed it doesn't take into account the shift modifier. I know the event.shiftKey property and use it, but right now I need to get the key value (eg: "A" or "a") which takes into account the shift key modifier. At first I used String.toLowerCase().. But I neglected to think of number keys, to give one example: "5" (without shift) and "%" (with shift). I need to differentiate between the two in my program. What's an easy way to get the key char value?

• javascript
• events
• char
• key

Share Improve this question Follow asked Jul 26, 2010 at 17:11 AlanAlan 2,12955 gold badges2525 silver badges2828 bronze badges 4

• what is the context of the question. Are you trying to see if the ShiftKey was pressed during a keypress, keyup, keydown event. Or are you evaluating a string of characters and want to know if it is upper/lowercase or number/special character? – John Hartsock Commented Jul 26, 2010 at 17:23
• I know how to check if the shift key is pressed during a key event. What I am asking is if there is any way to get the character of the key pressed (a method that takes into account the shift key) – Alan Commented Jul 26, 2010 at 17:26
• It's still not clear what you want. Do you want the actual character that was typed? The actual physical key that was pressed? – Tim Down Commented Jul 26, 2010 at 19:08
• I have been using String.fromCharCode() to get the key VALUE from a keycode as so: String.fromCharCode(/* KEYCODE FOR 'A' */) // 'A' Whether I hold down shift or not the value is always "A" (capital A). Now there is still no problem. In this case I just check if the shift key is not down (and caps lock is off) and use String.toLowerCase(). This works as expected (the value is "a" normally and "A" with shift). Now the trouble comes when I type numbers (since String.toUpperCase("1")=="1") what I really want Is something to apply shift so that I get: ("1" without shift and "!" with shift) – Alan Commented Jul 29, 2010 at 19:57

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4 Answers 4

Sorted by: Reset to default 8

This brute force technique isn't the prettiest, but it seems to work. I'm in search of the same functionality.

function mapKeyPressToActualCharacter(isShiftKey, characterCode) {
    if ( characterCode === 27 || characterCode === 8 || characterCode === 9 || characterCode === 20 || characterCode === 16 || characterCode === 17 || characterCode === 91 || characterCode === 13 || characterCode === 92 || characterCode === 18 ) {
        return false;
    }
    if (typeof isShiftKey != "boolean" || typeof characterCode != "number") {
        return false;
    }
    var characterMap = [];
    characterMap[192] = "~";
    characterMap[49] = "!";
    characterMap[50] = "@";
    characterMap[51] = "#";
    characterMap[52] = "$";
    characterMap[53] = "%";
    characterMap[54] = "^";
    characterMap[55] = "&";
    characterMap[56] = "*";
    characterMap[57] = "(";
    characterMap[48] = ")";
    characterMap[109] = "_";
    characterMap[107] = "+";
    characterMap[219] = "{";
    characterMap[221] = "}";
    characterMap[220] = "|";
    characterMap[59] = ":";
    characterMap[222] = "\"";
    characterMap[188] = "<";
    characterMap[190] = ">";
    characterMap[191] = "?";
    characterMap[32] = " ";
    var character = "";
    if (isShiftKey) {
        if ( characterCode >= 65 && characterCode <= 90 ) {
            character = String.fromCharCode(characterCode);
        } else {
            character = characterMap[characterCode];
        }
    } else {
        if ( characterCode >= 65 && characterCode <= 90 ) {
            character = String.fromCharCode(characterCode).toLowerCase();
        } else {
            character = String.fromCharCode(characterCode);
        }
    }
    return character;
}

It all depends on the event you are binding to. String.fromCharCode() will account for shiftKey during the onkeypress event. It will not, however, pay attention to it during the onkeydown event.

Expanding on wsams response, here is a more complete solution which takes more memory but is more performant

var characterMapShift = [];
characterMapShift[8] = "";
characterMapShift[9] = "";
characterMapShift[13] = "\n";
characterMapShift[16] = "";
characterMapShift[17] = "";
characterMapShift[18] = "";
characterMapShift[19] = "";
characterMapShift[20] = "";
characterMapShift[27] = "";
characterMapShift[32] = " ";
characterMapShift[33] = "";
characterMapShift[34] = "";
characterMapShift[35] = "";
characterMapShift[36] = "";
characterMapShift[37] = "";
characterMapShift[38] = "";
characterMapShift[39] = "";
characterMapShift[40] = "";
characterMapShift[45] = "";
characterMapShift[46] = "";
characterMapShift[48] = ")";
characterMapShift[49] = "!";
characterMapShift[50] = "@";
characterMapShift[51] = "#";
characterMapShift[52] = "$";
characterMapShift[53] = "%";
characterMapShift[54] = "^";
characterMapShift[55] = "&";
characterMapShift[56] = "*";
characterMapShift[57] = "(";
characterMapShift[59] = ":";
characterMapShift[61] = "+";
characterMapShift[65] = "A";
characterMapShift[66] = "B";
characterMapShift[67] = "C";
characterMapShift[68] = "D";
characterMapShift[69] = "E";
characterMapShift[70] = "F";
characterMapShift[71] = "G";
characterMapShift[72] = "H";
characterMapShift[73] = "I";
characterMapShift[74] = "J";
characterMapShift[75] = "K";
characterMapShift[76] = "L";
characterMapShift[77] = "M";
characterMapShift[78] = "N";
characterMapShift[79] = "O";
characterMapShift[80] = "P";
characterMapShift[81] = "Q";
characterMapShift[82] = "R";
characterMapShift[83] = "S";
characterMapShift[84] = "T";
characterMapShift[85] = "U";
characterMapShift[86] = "V";
characterMapShift[87] = "W";
characterMapShift[88] = "X";
characterMapShift[89] = "Y";
characterMapShift[90] = "Z";
characterMapShift[91] = "";
characterMapShift[92] = "";
characterMapShift[93] = "";
characterMapShift[96] = "0";
characterMapShift[97] = "1";
characterMapShift[98] = "2";
characterMapShift[99] = "3";
characterMapShift[100] = "4";
characterMapShift[101] = "5";
characterMapShift[102] = "6";
characterMapShift[103] = "7";
characterMapShift[104] = "8";
characterMapShift[105] = "9";
characterMapShift[106] = "*";
characterMapShift[107] = "+";
characterMapShift[109] = "_";
characterMapShift[107] = "+";
characterMapShift[111] = "/";
characterMapShift[112] = "";
characterMapShift[113] = "";
characterMapShift[114] = "";
characterMapShift[115] = "";
characterMapShift[116] = "";
characterMapShift[117] = "";
characterMapShift[118] = "";
characterMapShift[119] = "";
characterMapShift[120] = "";
characterMapShift[121] = "";
characterMapShift[122] = "";
characterMapShift[123] = "";
characterMapShift[144] = "";
characterMapShift[145] = "";
characterMapShift[186] = ":";
characterMapShift[187] = "+";
characterMapShift[188] = "<";
characterMapShift[189] = "_";
characterMapShift[190] = ">";
characterMapShift[191] = "?";
characterMapShift[192] = "~";
characterMapShift[219] = "{";
characterMapShift[220] = "|";
characterMapShift[221] = "}";
characterMapShift[222] = "\"";

var characterMap = [];
characterMap[8] = "";
characterMap[9] = "";
characterMap[13] = "\n";
characterMap[16] = "";
characterMap[17] = "";
characterMap[18] = "";
characterMap[19] = "";
characterMap[20] = "";
characterMap[27] = "";
characterMap[32] = " ";
characterMap[33] = "";
characterMap[34] = "";
characterMap[35] = "";
characterMap[36] = "";
characterMap[37] = "";
characterMap[38] = "";
characterMap[39] = "";
characterMap[40] = "";
characterMap[45] = "";
characterMap[46] = "";
characterMap[48] = "0";
characterMap[49] = "1";
characterMap[50] = "2";
characterMap[51] = "3";
characterMap[52] = "4";
characterMap[53] = "5";
characterMap[54] = "6";
characterMap[55] = "7";
characterMap[56] = "8";
characterMap[57] = "9";
characterMap[59] = ";";
characterMap[61] = "=";
characterMap[65] = "a";
characterMap[66] = "b";
characterMap[67] = "c";
characterMap[68] = "d";
characterMap[69] = "e";
characterMap[70] = "f";
characterMap[71] = "g";
characterMap[72] = "h";
characterMap[73] = "i";
characterMap[74] = "j";
characterMap[75] = "k";
characterMap[76] = "l";
characterMap[77] = "m";
characterMap[78] = "n";
characterMap[79] = "o";
characterMap[80] = "p";
characterMap[81] = "q";
characterMap[82] = "r";
characterMap[83] = "s";
characterMap[84] = "t";
characterMap[85] = "u";
characterMap[86] = "v";
characterMap[87] = "w";
characterMap[88] = "x";
characterMap[89] = "y";
characterMap[90] = "z";
characterMap[91] = "";
characterMap[92] = "";
characterMap[93] = "";
characterMap[96] = "0";
characterMap[97] = "1";
characterMap[98] = "2";
characterMap[99] = "3";
characterMap[100] = "4";
characterMap[101] = "5";
characterMap[102] = "6";
characterMap[103] = "7";
characterMap[104] = "8";
characterMap[105] = "9";
characterMap[106] = "*";
characterMap[107] = "+";
characterMap[109] = "_";
characterMap[107] = "+";
characterMap[111] = "/";
characterMap[112] = "";
characterMap[113] = "";
characterMap[114] = "";
characterMap[115] = "";
characterMap[116] = "";
characterMap[117] = "";
characterMap[118] = "";
characterMap[119] = "";
characterMap[120] = "";
characterMap[121] = "";
characterMap[122] = "";
characterMap[123] = "";
characterMap[144] = "";
characterMap[145] = "";
characterMap[186] = ";";
characterMap[187] = "=";
characterMap[188] = ",";
characterMap[189] = "-";
characterMap[190] = ".";
characterMap[191] = "/";
characterMap[192] = "`";
characterMap[219] = "[";
characterMap[220] = "\\";
characterMap[221] = "]";
characterMap[222] = "'";

function mapKeyPressToActualCharacter(isShiftKey, characterCode) {
    if (typeof isShiftKey != "boolean" || typeof characterCode != "number") {
        return false;
    }

    if (isShiftKey) {
        return characterMapShift[characterCode];
    } else {
        return characterMap[characterCode];
    }
}

Way too complicated. I wonder if this works on the dead keys (`~^'"). This is the easy way:

var charCode = event.key.charCodeAt(0); var character = String.fromCharCode(charCode);

You also have to realise that String.fromCharCode(event.keyCode) is very wrong. A charCode is not the same as a keyCode.

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