How to pass variable to href in javascript?

问题:

How to pass this variable value here? Below code is not working. And all other discussions on Stackoverflow are unclear.

<script type="text/javascript">
        function check()
        {
            var dist = document.getElementById('value');
            if (dist!=""){
                window.location.href="district.php?dist="+dist;
            }
            else
               alert('Oops.!!');
        }
</script>

And my HTML code is:

<select id="value" name="dist" onchange="return check()">

回答1:

You have to fetch field value using .value as you are passing whole object to the URL as document.getElementbyId('value') returns whole field object.

var dist = document.getElementById('value').value;

So your function should be like this

function check() {
    var dist = document.getElementById('value').value; // change here
    if (dist != "") {
        window.location.href = "district.php?dist=" + dist;
    } else
        alert('Oops.!!');
}

回答2:

You have fetch value of the field, Currently you are using DOM object

Use

 var dist = document.getElementById('value').value;

OR

Use

 if (dist.value!=""){
     window.location.href="district.php?dist="+dist.value;

instead of

if (dist!=""){
     window.location.href="district.php?dist="+dist;

回答3:

Try this:

function check() {
    var dist = document.getElementById('value').value;

    if (dist) {
        window.location.href = "district.php?dist=" + dist;
    } else {
        alert('Oops.!!');
    }
}

回答4:

Try this:

var dist = document.getElementById('value').value;
if (dist != "") {
 window.location.href="district.php?dist="+dist;
}

回答5:

You have to make some correction in your function..

function check()
    {
        var dist = document.getElementById('value').value;  //for input text value
       if (dist!==""){  //  for comparision
           window.location.href="district.php?dist="+dist;
       }
       else
           alert('Oops.!!');
    }