如何使用javascript清除文本框

Question

I have a

<input type="text" value="A new value">

I need a javascript method to clear the value of the textbox when the focus is on the textbox.

How can this be achieved?

Answer 1

just get element using

   function name()
   {  
   document.getElementById('elementid').value = "";
   }

you can call this function on onfocus event of textbox and clear the value

Answer 2

It sounds like you're trying to use a "watermark" (a default value that clears itself when the user focuses on the box). Make sure to check the value before clearing it, otherwise you might remove something they have typed in! Try this:

<input type="text" value="A new value" onfocus="if(this.value=='A new value') this.value='';">

That will ensure it only clears when the value is "A new value".

Answer 3

<input type="text" value="A new value" onfocus="javascript: if(this.value == 'A new value'){ this.value = ''; }" onblur="javascript: if(this.value==''){this.value='A new value';}" />

Answer 4

For those coming across this nowadays, this is what the placeholder attribute was made to do. No JS necessary:

<input type="text" placeholder="A new value">

Answer 5

简单的一个

onfocus="javascript:this.value=''" onblur="javascript: if(this.value==''){this.value='Search...';}"

Answer 6

使用......

<input type="text" name="yourName" placeholder="A new value" />

Answer 7

just set empty string

    <input type="text" id="textId" value="A new value">
    document.getElementById('textId').value = '';

Answer 8

在文本框的输入标记中给出：

onClick="(this.value='')" 

Answer 9

If using jQuery is acceptable:

jQuery("#myTextBox").focus( function(){ 
    $(this).val(""); 
} );

Answer 10

使用像这样的onfocus和onblur事件：

<input type="text" name="yourName" value="A new value" onfocus="if (this.value == 'A new value') this.value = '';" onblur="if (this.value == '') this.value = 'A new value';">

Answer 11

<input type="text" name="yourName" value="A new value" onfocus="if (this.value == 'A new value') this.value =='';" onblur="if (this.value=='') alert('Please enter a value');" />

Answer 12

使用javascript的Onfous和onblur文本框

   <input type="text" value="A new value" onfocus="if(this.value=='A new value') this.value='';" onblur="if(this.value=='') this.value='A new value';"/>

Answer 13

For my coffeescript peeps!

#disable Delete button until reason is entered
$("#delete_event_button").prop("disabled", true)
$('#event_reason_is_deleted').click ->
    $('#event_reason_is_deleted').val('')
    $("#delete_event_button").prop("disabled", false)

Answer 14

<input type="text" value="A new value" onfocus="this.value='';">

然而，对于那些第二次关注元素例如纠正某些事物的用户来说，这将是非常充实的。

Answer 15

Your HTML code,

jquery code,

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