jquery clear input

JQuery clear input - Make form input easier

In front-end development, we usually need to use forms to collect data entered by users. When the user completes their input, we need to clear the content in the form to facilitate the next input. In traditional HTML, we could add a reset button to each form element and then use JavaScript to clear the input. However, this method is not only cumbersome but also has poor fault tolerance. Using JQuery makes clearing form inputs easier and more reliable.

This article will introduce the basic methods and techniques of using JQuery to clear input, as well as the scenarios and techniques of clearing input commonly used in actual development, making your form input easier.

1. Basic methods and techniques

1. Clear the contents of a single input box

If you only need to clear the contents of a single input box, you can use the .val() method .

For example, if you have an input box with the ID "input1", you can use the following code to clear the contents of the input box:

$("#input1").val("");

2. Clear the contents of multiple input boxes

If you need to clear the contents of multiple input boxes, you can use a class selector to select these elements. For example, if you have three input boxes with the class name "input", you can use the following code to clear the contents of these input boxes:

$(".input").val("");

3. Clear the contents of all input boxes in the form

If you need to clear all input boxes in the form, you can use the form element selector to select all input boxes in the form, and then use the .val() method to clear their contents.

For example, if you have a form with the ID "form1", you can use the following code to clear the contents of all input boxes in the form:

$("#form1 :input").val("");

In the above code, :input is a A special selector that can select all input boxes, text fields, drop-down boxes, etc. in form elements. When you call it using the .val() method, it clears the contents of these elements.

4. Clear all content in the form

If you need to clear all the content in the form, including not only input boxes, but also drop-down boxes, radio boxes, check boxes, etc., You can use the form element selector to select a form element, and then use the .reset() method to reset the form.

For example, if you have a form with the ID "form1", you can use the following code to clear all the content in the form:

document.getElementById("form1").reset();

In the above code, the reset() method will The values ​​of all input boxes, drop-down boxes, radio buttons, and check boxes are reset to their default values.

2. Common scenarios and techniques

1. Clear the default value in the form

When the input box, drop-down box and other elements in the form have default values ​​set, if If the user wants to re-enter, they need to manually delete these default values. To reduce user effort, you can use JQuery to clear all default values ​​in the form after the page loads.

For example, if you have a form with the ID "form1" and you set the default value "Please enter a user name" in one of the input boxes, you can use the following code to clear all input boxes in the form. Default value:

$(document).ready(function(){
  $("#form1 :input").each(function(){
    if($(this).val() == $(this).attr("placeholder")){
      $(this).val("");
    }
  });
});

In the above code, the $(document).ready() function will be executed after the page is loaded, and then the .each() function will be used to traverse all input boxes in the form. If the value in the input box is equal to the corresponding placeholder attribute value, use the .val() method to clear it. At this point, the user can enter content directly without manually deleting the default value.

2. Operations after clearing the form

In actual development, we often need to perform certain operations after clearing the form. For example, when a form is submitted successfully, we might want to clear the form and display a success message. To prevent the user from seeing the form elements become blank as they are cleared, we can hide the form elements before clearing the form, and then show them after clearing them.

For example, you have a form with the ID "form1". When the user clicks the submit button, the form will be submitted. In order to avoid the user seeing a blank form while the form is being cleared, you can use the following code:

$("#submit_btn").click(function(){
  // 隐藏表单
  $("#form1 :input").hide();
  
  // 提交表单
  $.ajax({
    url: "submit.php",
    method: "post",
    data: $("#form1").serialize(),
    success: function(response){
      // 显示成功消息
      alert("提交成功！");
      
      // 清空表单
      $("#form1 :input").val("");
      
      // 显示表单
      $("#form1 :input").show();
    }
  });
});

In the above code, when the user clicks the submit button, the form element is hidden. The form data is then submitted to the server using AJAX methods. If the submission is successful, a success message will be displayed. Then, use the .val() method to clear the contents of all input boxes in the form. Finally, the form element is redisplayed.

Summary

This article introduces how to use JQuery to clear input and make form input easier. Basic clear input methods include clearing the contents of a single input box, clearing the contents of multiple input boxes, clearing the contents of all input boxes in the form, and clearing all content in the form. In addition, we also introduced scenarios and techniques for clearing input that are commonly used in actual development, such as clearing the default value in the form and operations after clearing the form. Use these tips to make clearing form input easier and more reliable.

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