alert a variable value

Question

How do I display the value of a variable in javascript in an alert box?

For example I've got a variable x=100 and alert(x) isn't working.

the script used in grease monkey is here

var inputs = document.getElementsByTagName('input');

var new;
for (i=0; i<inputs.length; i++) {
  if (inputs[i].getAttribute("name") == "ans") {   
new=inputs[i].getAttribute("value"));

alert(new)

  }
}

Answer 1

A couple of things:

1. You can't use new as a variable name, it's a reserved word.
2. On input elements, you can just use the value property directly, you don't have to go through getAttribute. The attribute is "reflected" as a property.
3. Same for name.

So:

var inputs, input, newValue, i;

inputs = document.getElementsByTagName('input');
for (i=0; i<inputs.length; i++) {
    input = inputs[i];
    if (input.name == "ans") {   
        newValue = input.value;
        alert(newValue);
    }
}

Answer 2

If you're using greasemonkey, it's possible the page isn't ready for the javascript yet. You may need to use window.onReady.

var inputs;

function doThisWhenReady() {
    inputs = document.getElementsByTagName('input');

    //Other code here...
}

window.onReady = doThisWhenReady;