Javascript 请解释一下原因：（原因已经给出。提供一个解释，我会投票。不要只是把HTML作为答案。 <html> <head> <script src="http://ajax.googleapis.com_Javascript_Jquery_Html_Forms

Javascript 请解释一下原因：（原因已经给出。提供一个解释，我会投票。不要只是把HTML作为答案。 <html> <head> <script src="http://ajax.googleapis.com

javascript jquery html forms

Javascript 请解释一下原因：（原因已经给出。提供一个解释，我会投票。不要只是把HTML作为答案。 <html> <head> <script src="http://ajax.googleapis.com,javascript,jquery,html,forms,Javascript,Jquery,Html,Forms,请解释一下原因：（原因已经给出。提供一个解释，我会投票。不要只是把HTML作为答案。 <html> <head> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script> </head> <body> <form id="shopping_cart"

请解释一下原因：（原因已经给出。提供一个解释，我会投票。不要只是把HTML作为答案。

    <html>
    <head>

        <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

    </head>
    <body>

<form id="shopping_cart" onsubmit="" action="" method="" target=""> 
    <select id="chooseproduct" onchange="getprice()">
        <option name="2.0" value="FirstProduct">FirstProduct</option>
        <option name="2.5" value="SecondProduct">SecondProduct</option>
        <option name="3.5" value="ThirdProduct">ThirdProduct</option>
        <option name="4.0" value="FourthProduct">FourthProduct</option>
    </select>

    <select id="choosecolor" onchange="getprice()">
        <option name="3.2" value="FirstColor">FirstColor</option>
        <option name="4.6" value="SecondColor">SecondColor</option>
        <option name="5.8" value="ThirdColor">ThirdColor</option>
        <option name="7.3" value="FourthColor">FourthColor</option>
    </select>   

    <select id="choosesize" onchange="getprice()">
        <option name="8.0"  value="FirstSize">FirstSize</option>
        <option name="9.0"  value="SecondSize">SecondSize</option>
        <option name="12.5" value="ThirdSize">ThirdSize</option>
        <option name="16.0" value="FourthSize">FourthSize</option>
    </select>       


    <div>Result is:</div><div id="result"></div>



        <script type="text/javascript">
            function getprice()
        {
                var product = document.getElementsByName("chooseproduct").name;
                var color = document.getElementsByName("choosecolor").name;
                var size = document.getElementsByName("choosesize").name;
                var calculate = product*color*size;
                var result = document.getElementsByName("result");
                    result.innerHTML = calculate;

        }
        </script>
</form>

   </body>
</html>

var objJson = { "toto" : val1, "toto2" : val2};

$("#ElementID").attr("attributName", JSON.strigify(objJson));

var objJson = JSON.parse($("#ElementID").attr("attributeName"));

$('select').change(function(){
  var amt = $('#result').text();
  var newAmt = Number(amt) + Number($(this).val());
  console.log(newAmt);
});

$(this).val() and $(this).attr('name')

    <form id="shopping_cart" onsubmit="" action="" method="" target=""> 
        <select id="chooseproduct" onchange="getprice()">
            <option value="2.0" >FirstProduct</option>
            <option value="2.5" >SecondProduct</option>
            <option value="3.5" >ThirdProduct</option>
            <option value="4.0" >FourthProduct</option>
        </select>
        <select id="choosecolor" onchange="getprice()">
            <option value="3.2">FirstColor</option>
            ...
        </select>   
        <select id="choosesize" onchange="getprice()">
            <option value="8.0">FirstSize</option>
            ...
        </select>       
        <div>Result is:</div><div id="result"></div>

    <script type="text/javascript">
    function getprice(){   
        product = $("#chooseproduct").val();
        color = $("#choosecolor").val();
        size = $("#choosesize").val();

        var calculate = product*color*size;
        var result = $("#result");
        result.html($("option:selected","#chooseproduct").text());
    }
</script></form>

<form id="shopping_cart" onsubmit="" action="" method="" target=""> 
    <select id="chooseproduct" onchange="getprice()">
        <option data-price="2.0" value="FirstProduct">FirstProduct</option>
        <option data-price="2.5" value="SecondProduct">SecondProduct</option>
        <option data-price="3.5" value="ThirdProduct">ThirdProduct</option>
        <option data-price="4.0" value="FourthProduct">FourthProduct</option>
    </select>

    <select id="choosecolor" onchange="getprice()">
        <option data-price="3.2" value="FirstColor">FirstColor</option>
        <option data-price="4.6" value="SecondColor">SecondColor</option>
        <option data-price="5.8" value="ThirdColor">ThirdColor</option>
        <option data-price="7.3" value="FourthColor">FourthColor</option>
    </select>   

    <select id="choosesize" onchange="getprice()">
        <option data-price="8.0"  value="FirstSize">FirstSize</option>
        <option data-price="9.0"  value="SecondSize">SecondSize</option>
        <option data-price="12.5" value="ThirdSize">ThirdSize</option>
        <option data-price="16.0" value="FourthSize">FourthSize</option>
    </select>       


    <div>Result is:</div><div id="result"></div>
<script type="text/javascript">
function getprice()
{
    var calculate = 0;

    var productEle = document.getElementById("chooseproduct");
    var colorEle = document.getElementById("choosecolor");
    var sizeEle = document.getElementById("choosesize");
    if (productEle.selectedIndex == -1 || colorEle.selectedIndex == -1 || sizeEle.selectedIndex == -1) {
        // Do something when they're not all selected
    } else {
        var product = productEle.options[productEle.selectedIndex].getAttribute("data-price")
        var color = colorEle.options[colorEle.selectedIndex].getAttribute("data-price")
        var size = sizeEle.options[sizeEle.selectedIndex].getAttribute("data-price")
        calculate = product*color*size;
    }    
    var result = document.getElementById("result");
    result.innerHTML = calculate;

}
</script>
</form>