如何通过 JavaScript 设置输入隐藏字段的值？

Question

I am trying to call the resetyear function and it's getting called also, but the flow stops at alert("over") . It doesn't transfer its control to resetmaster .

    String flag = "";
    flag = (String) session.getAttribute("flag");
    System.out.println("flag = " + flag);
    if (flag == null) {
        flag = "";
    }
    if (flag.equals("yes")) {
%>   
<script>
   
   alert(1);
  // resetyear();
    dontreset();
    //document.getElementById("checkyear").value = "1";
    //alert(document.getElementById("checkyear").value);
    
</script>
<%} else if(flag.equals("no"))
    {%>
<script>
    alert(2);
    //document.getElementById("checkyear").value = "2";
    //alert(document.getElementById("checkyear").value);
    resetyear();
</script>
<%}else{}%>


function resetyear(){

if(confirm("DO YOU WANT TO RESET THE YEAR?"))
{
    alert("hello");
    //document.forms['indexform'].action = "resetmaster";
    //alert(document.forms['indexform'].action);
    //document.forms['indexform'].submit();  
    alert("over");
    form.action = "resetmaster";
    form.submit();
    alert(1);
}

Answer 1

For me it works:

document.getElementById("checkyear").value = "1";
alert(document.getElementById("checkyear").value);

http://jsfiddle.net/zKNqg/

Maybe your JS is not executed and you need to add a function() {} around it all.

Answer 2

You need to run your script after the element exists. Move the <input type="hidden" name="checkyear" id="checkyear" value=""> to the beginning.

Answer 3

It seems to work fine in Google Chrome. Which browser are you using? Here the proof http://jsfiddle.net/CN8XL/

Anyhow you can also access to the input value parameter through the document.FormName.checkyear.value . You have to wrap in the input in a <form> tag like with the proper name attribute, like shown below:

<form name="FormName">
    <input type="hidden" name="checkyear" id="checkyear" value="">
</form>

Have you considered using the jQuery Library? Here are the docs for .val() function .

Answer 4

The first thing I will try - determine if your code with alerts is actually rendered. I see some server "if" code in what you posted, so may be condition to render javascript is not satisfied. So, on the page you working on, right-click -> view source. Try to find the js code there. Please tell us if you found the code on the page.

Answer 5

Your code for setting value for hidden input is correct. Here is the example . Maybe you have some conditions in your if statements that are not allowing your scripts to execute.