<input type="text" id="txt_purchaseItem_Count" class="textInput" οnkeyup="TranTotal();"

                    οnkeypress="return CheckKey(this,event);" />

                <span name="txt_purchaseItem_Count" value="数量不能为空！" regexp="empty" style="color: Red">

                    *</span>

 

//计算值

function TranTotal() {

    var purchaseItem_Count = document.getElementById("txt_purchaseItem_Count").value;

    var purchaseItem_UnitCost = document.getElementById("txt_purchaseItem_UnitCost").value;

    document.getElementById("txt_TotalValue").value = Math.round((purchaseItem_Count * purchaseItem_UnitCost) * 100) / 100;

}

//验证只能输入数字，最多只能两们小数点

function CheckKey(obj, e) {

    var key = window.event ? e.keyCode : e.which;

    var keychar = String.fromCharCode(key);

    reg = /\d|\./;

    var result = reg.test(keychar);

    if (result) {

        if (e.keyCode == 46)

            result = !(obj.value.split('.').length > 1);

        else

            result = !(obj.value.split('.').length > 1 && obj.value.split('.')[1].length > 1);

    }

    if (!result) {

        return false;

    }

    else {

        return true;

    }

}