Getting value from input box in html in external Javascript

Question

I have an HTML page and and external JavaScript file. How do I access the value of an input tag from the HTML page in JavaScript? My HTML is as follows:

<form name="formxml">
<input type="text" name="xmlname"/>
<input type="submit" value="Click me please" onclick="loadxml()"/>
</form>

In the Javascript file, I was trying:

var name = document.formxml.xmlname.value

but this gives an error of "document.formxml is undefined"

What should I do?

Answer 1

Looks like the external js can't find the form yet because it's parsed before the page is rendered? Not sure about it, but putting it in a function and calling the function on the page (when it's done loading) does work:

function foo () {
  var name = document.formxml.xmlname.value;
  alert(name);
}

and

<form action="" method="post" name="formxml">
  <input type="text" name="xmlname" value="123" id="xmlname">
  <input type="button" onclick="foo();">
</form>

Answer 2

将id属性添加到输入标签后，可以使用以下命令

document.getElementById('id').value

Answer 3

maybe document. forms .formxml.xmlname.value

Answer 4

您还可以使用：

var name = document.forms[0].xmlname.value; //where [0] means the first form on the page

Answer 5

var name = document.formxml.value; //Will not work in all browsers
var name = document.forms[0].xmlname.value; //safest if the form is the first on the page
var name = document.getElementById('inputId').value; //works in basically everything assuming the browser has DHTML (which is like everything).

The last one requires your input elem to have an id="inputId" added to it.

Also your code will work, assuming the form exists when the external js is loaded (which is why forms[0] will work here and formxml will not.

Answer 6

Try this

<script>
    function yourfunction()
    {
       var x = document.getElementsByName("fieldname").value;
    }
</script>