jquery modifies form value

jQuery is a popular JavaScript library that can be easily used with HTML, CSS and JavaScript. In web development, we often need to modify the values ​​in form elements. At this time, we can use jQuery to simplify the code.

This article will introduce how to use jQuery to modify the values ​​in the form, add, delete, modify attribute values ​​​​on the form elements and set the values ​​​​of the form elements. The following are detailed steps and code examples:

1. Modify the value of the form element

Use the .val() function to get or set the form element value. For example, to change the value of an input box to "hello", you can use the following code:

$('#myInput').val('hello');

Here #myInput represents the ID of the input box. If you want to modify the value of a radio button, multi-select box or drop-down box, you can also use the .val() function, but please note that the value must match the value of the option.

2. Get the value of the form element

Use the .val() function to get the value of the form element, for example:

var inputValue = $('#myInput').val();

HereinputValueThe variable will save the value of the input box. Similarly, if you want to get the value of a radio button, multi-select box or drop-down box, you can also use the .val() function.

3. Add or delete attribute values

To add or delete attribute values, you can use the .attr() function. For example, to set the readonly attribute of an input box to true, you can use the following code:

$('#myInput').attr('readonly', true);

To delete the attribute value, just change the second parameter Just set it to null. For example, to remove the disabled attribute of a button, you can use the following code:

$('#myButton').attr('disabled', null);

4. Get or modify the attribute value of a form element

Use .attr()The function can get the attribute value of the form element. For example, to get the type attribute value of an input box, you can use the following code:

var inputType = $('#myInput').attr('type');

To modify the attribute value, you can also use the .attr() function. For example, to change the src attribute of an image link to the address of another image, you would use the following code:

$('#myImage').attr('src', 'newImage.png');

5. Modify the style of a form element

Use the .css() function to modify the style of the form element. For example, to set the background color of a button to red, you can use the following code:

$('#myButton').css('background-color', 'red');

6. Modify the values ​​of multiple form elements at the same time

If you need to modify multiple form elements at the same time For the value of a form element, you can use the .each() function. For example, to set the value of all input boxes to "hello", you can use the following code:

$('input').each(function() {
  $(this).val('hello');
});

The $(this) here represents the input box currently being processed.

Finally, the above is a simple example. For more information, you can view jQuery’s official documentation. I hope this article can help you learn jQuery to modify form element values.

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