Clear text field value in JQuery

问题:

I understand this is an easy question but for some reason this just isn't working for me. I have a function that is triggered everytime a drop down menu is changed. Here is the relevant code that is suppose to grab the current value of the text field, if a value exists, clear it that is contained within the .change function:

var doc_val_check = $('#doc_title').attr("value");
    if (doc_val_check.length > 0) {
        doc_val_check == "";
    }

I feel like I am missing something very simple.

回答1:

doc_val_check == "";   // == is equality check operator

should be

doc_val_check = "";    // = is assign operator. you need to set empty value

                       // so you need =

You can write you full code like this:

var doc_val_check = $.trim( $('#doc_title').val() ); // take value of text 
                                                     // field using .val()
    if (doc_val_check.length) {
        doc_val_check = ""; // this will not update your text field
    }

To update you text field with a "" you need to try

$('#doc_title').attr('value', doc_val_check); 
// or 
$('doc_title').val(doc_val_check);

But I think you don't need above process.

---

In short, just one line

$('#doc_title').val("");

Note

.val() use to set/ get value in text field. With parameter it acts as setter and without parameter acts as getter.

Read more about .val()

回答2:

If you want to clear the text field, use:

$('#doc_title').val("");

回答3:

Instead of all those:

$('#doc_title').attr("value", "");

回答4:

What you need is:

if ($('#doc_title').val()) {
  $('#doc_title').val('');
}

回答5:

If you are using jQuery, then you can use this:

// var doc_val_check = $('#doc_title').val(); - No need of this!
if ($('#doc_title').val().length > 0) {
    $('#doc_title').val("");
}

回答6:

In simple way, you can use the following code to clear all the text field, textarea, dropdown, radio button, checkbox in a form.

function reset(){
    $('input[type=text]').val('');  
    $('#textarea').val(''); 
    $('input[type=select]').val('');
    $('input[type=radio]').val('');
    $('input[type=checkbox]').val('');  
}

回答7:

you can clear it by using this line

$('#TextBoxID').val("");

回答8:

We can use this for text clear

$('input[name="message"]').val("");  

回答9:

You are comparing doc_val_check with an empty string. You want to assign the empty string to doc_val_check

so it should be this:

doc_val_check = "";

回答10:

For the most part you just set the .val() method. All of the answers are pretty accurate, just wanted to post my results to anyone who may need to set the value via the client id that gets rendered.

 $('#' + '<%= doc_title.ClientID %>').val(null);

回答11:

Use jQuery.prototype.val to get/set field values:

var value = $('#doc_title').val();    // get value
$('#doc_title').val('');    // clear value

回答12:

    First Name: <input type="text" autocomplete="off" name="input1"/>
    <br/>
    Last Name: <input type="text" autocomplete="off" name="input2"/>
    <br/>
    <input type="submit" value="Submit" />
</form>

回答13:

$('#[element id]').val(null);

or

$('.[element class]').val(null);

回答14:

If you want to have element with visible blank text just do this:

$('#doc_title').html(' ');