JavaScript Coder

Javascript Form

Doing real-time calculations in a form using JavaScript

In this tutorial, we will learn how to perform calculations using JavaScript. It is quite often required to do calculations online in order forms, request quote forms and the like. This tutorial will show you how to use different form elements like drop-down list, radio button, check box and text box in a calculation. We will be using a ‘cake order form’ as an example. As the user makes selections in the form, the total price is calculated in real time.

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Can JavaScript email a form?

NO! JavaScript can't email a form! but, there are alternatives to send the form data to an email address. There is no direct method provided by JavaScript to send the data submitted in the form to an email address. The main concern for not providing a ‘JavaScript email form’ feature is security. Suppose there is a feature in JavaScript to send email. Some malicious coder can write a script to send email to some address immediately when you visit their page.

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How to Submit a Form Using JavaScript

Generally, a form is submitted when the user presses a submit button. However, sometimes, you may need to submit the form programmatically using JavaScript. JavaScript provides the form object that contains the submit() method. Use the ‘id’ of the form to get the form object. For example, if the name of your form is ‘myform’, the JavaScript code for the submit call is: document.forms["myform"].submit(); But, how to identify a form? Give an id attribute in the form tag

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How to get the value of a form element : check box and radio button

This is the third article in the getting form element values using JavaScript series. In this article we will see how to get the value of check box and radio button. Getting a radio element and it's checked value Radio buttons in a form can be grouped together using the same name attribute, such that, if one of them is checked, all the others are automatically un-checked. Let us look at an example:

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How to get the value of a form element : Drop downs and lists

This article is in continuation of getting form element values using JavaScript series. Drop down list We can obtain a reference to this type of element using its name: oSelectOne = oForm.elements["select_one_element_name"]; To get the index of the selected option in the JavaScript options array of the select element, we can use the selectedIndex property of the select element object: index = oSelectOne.selectedIndex; We can now use this index to determine the value of the selected option:

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How to get the value of a form element using JavaScript

Please refer article: how to get JavaScript form object for information on getting a reference to the form object. In this article we demonstrate the use of JavaScript for accessing the values of form elements. Later, we will demonstrate all the concepts using a real world example. Text input element To obtain a reference to a text input element, here is some sample code: oText = oForm.elements["text_element_name"]; OR oText = oForm.

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Using JavaScript to access form objects when there are multiple forms

In order to access a form through JavaScript, we need to obtain a reference to the form object. One obvious way to approach, is to use the getElementById method. For instance, if we had a form with the id attribute "subscribe_frm", we could access the form in this way: var oForm = document.getElementById('subscribe_frm'); However, this approach has the limitation that the <form> tag must have an id attribute, as the getElementById method needs the id of an element in order to locate it in the DOM tree.

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Using JavaScript to reset or clear a form

Using an HTML ‘Reset’ button is an easy way to reset all form fields to their default values. For instance, the code snippet below shows an <input> field of type “reset”, which on being clicked resets all the form fields: <input type="reset" value="Reset Form"> In fact, we could also use the form's reset() method to achieve the same effect, using a simple button element: <input type="button" value="Reset Form" onClick="this.form.reset()" /> These methods are very convenient to use, but they do not provide the functionality of clearing all the fields, including their default values.

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How to set the value of a form element using Javascript

As we have seen in earlier articles, in order to work with forms in JavaScript, it is imperative to obtain references to the form object and its elements. In this article, we will be using the forms collection of the document object and the elements collection of the form object to set the values of the form elements. The syntax for accessing the form object is as below: oFormObject = document.

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How to set the value of a form field using Javascript PII

This is in continuation of the article: set the value of a form element using Javascript. In this section, we will see how to set the value of other input fields like hidden field, drop down list etc Setting the value of a hidden field using Javascript As in the case of ‘textarea’ and ‘text’ input elements, in order to set the value of a hidden input element in a form, we can use the following syntax:

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How to set the value of a form field using Javascript PIII

This is in continuation of the previous article: How to set the value of a form field using JavaScript Selecting options of a select element through javascript In Javascript, since each <option> tag inside a <select> tag, is placed in the options array of the select object, we can access each select option using a construct such as: selectObject.options[index] where, “index” refers to the position of the option in the array.

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How to use getElementById to get the elements in a form

There are many ways of accessing form elements, of which the easiest is by using the cross-browser W3C DOM document.getElementById() method. Before we learn more about this method, it would be useful to know something about the Document Object Model (DOM), the concept of HTML nodes or elements, and the concept of containers. Each time you load an HTML page, the web browser generates an internal representation of the page in the form of an inverted tree structure.

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