从表单传递参数到JavaScript函数

Question

I am having trouble trying to figure out how to do this. I want to, using fields in a form as variables call a JavaScript function.

I have this:

 <form> <select name="users" onchange="showUser(this.value)"> <option value="">Select a person:</option> <option value="1">Peter Griffin</option> <option value="2">Lois Griffin</option> <option value="3">Joseph Swanson</option> <option value="4">Glenn Quagmire</option> </select> </form> 

from an example but what I need is this, but doesn't work:

 <form onsubmit="myFunction(this.num_cluster)"> Num. Cluster: <input type="text" id="num_cluster"> <input type="submit"> </form> 

Cloud someone help me ? Thanks :)

Answer 1

Change id to name - after that you can access value of input field

 function myFunction(form, event) { event.preventDefault(); alert(form.num_cluster.value); } 

 <form onsubmit="return myFunction(this, event)"> Num. Cluster: <input name="num_cluster" type="text"> <input type="submit"> </form> 

As problem is little more interesting - we can extend our method onsubmit

 function s(form, event) { event.preventDefault(); var values = Array.prototype.slice.call(form.elements) // as form elements are not an array .filter(function(element) { return element.type !== 'submit'; // I don't need submit button }) .map(function(element) { return (element.name + ': ' + element.value); // get name and value for rest form inputs and assign them to values variable }); alert('values => ' + values.join(', ')) // finish } 

 <form onsubmit="return s(this, event)"> <p>Foo: <input type="text" name='foo' /> </p> <p>Bar: <input type="text" name='bar' /> </p> <p>Baz: <select name='baz'> <option value="lorem">lorem</option> <option value="ipsum">ipsum</option> </select> </p> <p> <input type="submit" /> </p> </form> 

Answer 2

function myFunction(){
  var value=document.getElementById("num_cluster").value;

///  value has the actual thing that you need
//... rest of your code
}

you can use this statement even in onsubmit event by directly writing java script there.