diff --git a/mix/qml.qrc b/mix/qml.qrc
index c47a7254f..784404270 100644
--- a/mix/qml.qrc
+++ b/mix/qml.qrc
@@ -63,5 +63,6 @@
         <file>qml/js/Printer.js</file>
         <file>qml/js/ansi2html.js</file>
         <file>qml/js/NetworkDeployment.js</file>
+        <file>qml/js/InputValidator.js</file>
     </qresource>
 </RCC>
diff --git a/mix/qml/QIntTypeView.qml b/mix/qml/QIntTypeView.qml
index a3c67aafc..c42e65654 100644
--- a/mix/qml/QIntTypeView.qml
+++ b/mix/qml/QIntTypeView.qml
@@ -21,8 +21,15 @@ Item
 			clip: true
 			selectByMouse: true
 			text: value
+			anchors.fill: parent
 			font.pointSize: dbgStyle.general.basicFontSize
 			color: dbgStyle.general.basicColor
+			MouseArea {
+				id: mouseArea
+				anchors.fill: parent
+				hoverEnabled: true
+				onClicked: textinput.forceActiveFocus()
+			}
 		}
 	}
 }
diff --git a/mix/qml/TransactionDialog.qml b/mix/qml/TransactionDialog.qml
index e7fe22e51..a4c896d3f 100644
--- a/mix/qml/TransactionDialog.qml
+++ b/mix/qml/TransactionDialog.qml
@@ -6,6 +6,7 @@ import QtQuick.Window 2.0
 import QtQuick.Controls.Styles 1.3
 import org.ethereum.qml.QEther 1.0
 import "js/TransactionHelper.js" as TransactionHelper
+import "js/InputValidator.js" as InputValidator
 import "."
 
 Dialog {
@@ -503,10 +504,22 @@ Dialog {
 				anchors.right: parent.right;
 
 				Button {
+
 					text: qsTr("OK");
 					onClicked: {
-						close();
-						accepted();
+						var invalid = InputValidator.validate(paramsModel, paramValues);
+						if (invalid.length === 0)
+						{
+							close();
+							accepted();
+						}
+						else
+						{
+							errorDialog.text = qsTr("some parameters are invalid:\n");
+							for (var k in invalid)
+								errorDialog.text += invalid[k].message + "\n";
+							errorDialog.open();
+						}
 					}
 				}
 
@@ -514,6 +527,12 @@ Dialog {
 					text: qsTr("Cancel");
 					onClicked: close();
 				}
+
+				MessageDialog {
+					id: errorDialog
+					standardButtons: StandardButton.Ok
+					icon: StandardIcon.Critical
+				}
 			}
 		}
 	}
diff --git a/mix/qml/js/InputValidator.js b/mix/qml/js/InputValidator.js
new file mode 100644
index 000000000..6e94dec6e
--- /dev/null
+++ b/mix/qml/js/InputValidator.js
@@ -0,0 +1,112 @@
+var nbRegEx = new RegExp('^[0-9]+$');
+function validate(model, values)
+{
+	var inError = [];
+	for (var k in model)
+	{
+		if (values[model[k].name])
+		{
+			var type = model[k].type.name;
+			var res;
+			if (type.indexOf("int") !== -1)
+				res = validateInt(type, values[model[k].name]);
+			else if (type.indexOf("bytes") !== -1)
+				res = validateBytes(type, values[model[k].name]);
+			else if (type.indexOf("bool") !== -1)
+				res = validateBool(type, values[model[k].name]);
+			else if (type.indexOf("address") !== -1)
+				res = validateAddress(type, values[model[k].name]);
+			else
+				res = validateAddress(type, values[model[k].name]); //we suppose that this is a ctr type.
+			if (!res.valid)
+				inError.push({ type: type, value: values, message: res.message });
+		}
+	}
+	return inError;
+}
+
+function validateInt(_type, _value)
+{
+	var ret = { valid: true, message: "" }
+	if (_value.indexOf("-") === 0)
+	{
+		_value = _value.substring(1);
+		if (_type.indexOf("uint") === -1)
+		{
+			ret.valid = false;
+			ret.message = "uint type cannot represent negative number";
+			return false;
+		}
+	}
+	ret.valid = nbRegEx.test(_value);
+	if (!ret.valid)
+		ret.message = _value + " does not represent " + _type + " type.";
+	else
+	{
+		var t = _type.replace("uint", "").replace("int", "");
+		var max = parseInt(t) / 4;
+		if (_value.length > max)
+		{
+			ret.valid = false;
+			ret.message = _type + " should not contains more than " + max + " digits";
+		}
+	}
+	return ret;
+}
+
+function validateAddress(_type, _value)
+{
+	var ret = { valid: true, message: "" }
+	if (_value.indexOf("<") === 0 && _value.indexOf(">") === _value.length - 1)
+	{
+		var v = _value.split(' - ');
+		console.log(JSON.stringify(v));
+		if (v.length !== 2 || !nbRegEx.test(v[1].replace(">", ""))) // <Contract - 2>
+		{
+			ret.valid = false;
+			ret.message = _value + " is not a valid token for address type.";
+		}
+	}
+	else if (_value.indexOf("0x") !== 0)
+	{
+		ret.valid = false
+		ret.message = "Address type should start with 0x.";
+	}
+	else
+	{
+		_value = _value.substring(2);
+		if (_value.length !== 40)
+		{
+			ret.valid = false
+			ret.message = "Address type should contain 40 characters.";
+		}
+	}
+	return ret;
+}
+
+function validateBytes(_type, _value)
+{
+	var ret = { valid: true, message: "" }
+	if (_value.length > parseInt(_type.replace("bytes", "")) )
+	{
+		ret.valid = false;
+		ret.message = _type + " should not contains more than " + _type.replace("bytes", "") + " characters";
+	}
+	return ret;
+}
+
+function validateBool(_type, _value)
+{
+	var ret = { valid: true, message: "" }
+	if (_value !== "1" && _value !== "0")
+	{
+		ret.valid = false;
+		ret.message = _value + " is not in the correct bool format";
+	}
+	return ret;
+}
+
+function validateEnum(_type, _value)
+{
+}
+