Tuesday, May 12, 2015

Amount Field Validation For TextBox In JavaScript

This article will help you set validations in textbox in such a way that the textbox can be only be an amount field such that it accepts only numeric along with 2 decimal points.

JavaScript Code:


function extractNumber(obj, decimalPlaces, allowNegative)
 {
    var temp = obj.value;
    var reg0Str = '[0-9]*';
    if (decimalPlaces > 0) {
        reg0Str += '\[\,\.]?[0-9]{0,' + decimalPlaces + '}';
    } else if (decimalPlaces < 0) {
        reg0Str += '\[\,\.]?[0-9]*';
    }
    reg0Str = allowNegative ? '^-?' + reg0Str : '^' + reg0Str;
    reg0Str = reg0Str + '$';
    var reg0 = new RegExp(reg0Str);
    if (reg0.test(temp)) return true;

    // first replace all non numbers
    var reg1Str = '[^0-9' + (decimalPlaces != 0 ? '.' : '') + (decimalPlaces != 0 ? ',' : '') + (allowNegative ? '-' : '') + ']';
    var reg1 = new RegExp(reg1Str, 'g');
    temp = temp.replace(reg1, '');

    if (allowNegative) {
        // replace extra negative
        var hasNegative = temp.length > 0 && temp.charAt(0) == '-';
        var reg2 = /-/g;
        temp = temp.replace(reg2, '');
        if (hasNegative) temp = '-' + temp;
    }

    if (decimalPlaces != 0) {
        var reg3 = /[\,\.]/g;
        var reg3Array = reg3.exec(temp);
        if (reg3Array != null) {
            // keep only first occurrence of .
            //  and the number of places specified by decimalPlaces or the entire string if decimalPlaces < 0
var reg3Right = temp.substring(reg3Array.index + reg3Array[0].length);
            reg3Right = reg3Right.replace(reg3, '');
            reg3Right = decimalPlaces > 0 ? reg3Right.substring(0, decimalPlaces) : reg3Right;
            temp = temp.substring(0, reg3Array.index) + '.' + reg3Right;
        }
    }

    obj.value = temp;
}
function blockNonNumbers(obj, e, allowDecimal, allowNegative) {
    var key;
    var isCtrl = false;
    var keychar;
    var reg;
    if (window.event) {
        key = e.keyCode;
        isCtrl = window.event.ctrlKey
    }
    else if (e.which) {
        key = e.which;
        isCtrl = e.ctrlKey;
    }

    if (isNaN(key)) return true;

    keychar = String.fromCharCode(key);

    // check for backspace or delete, or if Ctrl was pressed
    if (key == 8 || isCtrl) {
        return true;
    }

    reg = /\d/;
    var isFirstN = allowNegative ? keychar == '-' && obj.value.indexOf('-') == -1 : false;
    var isFirstD = allowDecimal ? keychar == '.' && obj.value.indexOf('.') == -1 : false;
    var isFirstC = allowDecimal ? keychar == ',' && obj.value.indexOf(',') == -1 : false;
    return isFirstN || isFirstD || isFirstC || reg.test(keychar);
}
function blockInvalid(obj) {
    var temp = obj.value;
    if (temp == "-") {
        temp = "";
    }

    if (temp.indexOf(".") == temp.length - 1 && temp.indexOf(".") != -1) {
        temp = temp + "00";
    }
    if (temp.indexOf(".") == 0) {
        temp = "0" + temp;
    }
    if (temp.indexOf(".") == 1 && temp.indexOf("-") == 0) {
        temp = temp.replace("-", "-0");
    }
    if (temp.indexOf(",") == temp.length - 1 && temp.indexOf(",") != -1) {
        temp = temp + "00";
    }
    if (temp.indexOf(",") == 0) {
        temp = "0" + temp;
    }
    if (temp.indexOf(",") == 1 && temp.indexOf("-") == 0) {
        temp = temp.replace("-", "-0");
    }
    temp = temp.replace(",", ".");
    obj.value = temp;
}

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