jquery adds attribute cecked

In web development, submitting a form is a very common task. Forms typically include radio buttons and checkboxes to collect input from the user. In some cases, we may need to pre-select radio boxes or checkboxes by default. In this case, we can use jQuery to add the checked attribute to achieve our goal.

jQuery adds attributes checked

In jQuery, we can use the attr() method to add or modify the attributes of an element. However, for radio buttons and check boxes, we should pay attention to using the prop() method to set the checked attribute instead of using the attr() method. This is because the checked attribute actually represents a Boolean value, and the attr() method cannot correctly set Boolean attributes.

For example, if we want to pre-select a radio button box, we can use the following code:

$('input[name=sex][value=male]').prop('checked', true);

In this way, the radio button box named sex and the value male will be selected.

Similarly, if we want to pre-select a checkbox, we can use the following code:

$('input[name=hobby][value=sports]').prop('checked', true);

In this way, the checkbox named hobby and the value is sports will be selected.

In addition, we can also use another way to achieve the same effect, that is, add the checked attribute in the HTML element. However, this method is not flexible enough and is no longer suitable if we need to dynamically select or deselect radio boxes or checkboxes in the program.

For example, the following code snippet can pre-select a radio button in HTML:

<input type="radio" name="sex" value="male" checked>

However, if we want to cancel the selected state of the radio button, we need to manually modify the HTML code , which is obviously not a good solution.

Conclusion

Using jQuery to add the checked attribute is a simple and effective way to pre-select radio buttons and check boxes on a form. We can use the prop() method to set the checked attribute instead of using the attr() method. In this way, the correctness and reliability of the code can be guaranteed. At the same time, you can also dynamically select or deselect radio buttons or check boxes in the program, making form interaction more flexible and convenient.

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