Javascript allow textbox accept numbers and 2 decimal points only

<script type="text/javascript">// price text-box allow numeric and allow 2 decimal points only function extractNumber(obj, decimalPlaces, allowNegative) { var temp = obj.value; // avoid changing things if already formatted correctly 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 ? . : ) + (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; return isFirstN || isFirstD || reg.test(keychar); } // end of price text-box allow numeric and allow 2 decimal points only </script> <input type="text" name="price" value="" size="10" onblur="extractNumber(this,2,false);" onkeyup="extractNumber(this,2,false);" onkeypress="return blockNonNumbers(this, event, true, false);" />

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