在jsp中怎么实现163或126邮箱中添加附件那样？（急。。。。。）
------解决方案--------------------
<html>
<head>
<style>
a.addfile {
background-image:url(http://p.mail.163.com/js31style/lib/0703131650/163blue/f1.gif);
background-repeat:no-repeat;
background-position:-823px -17px;
display:block;
float:left;
height:20px;
margin-top:-1px;
position:relative;
text-decoration:none;
top:0pt;
width:80px;
}
input.addfile {
/*left:-18px;*/
}
input.addfile {
cursor:pointer !important;
height:18px;
left:-13px;
filter:alpha(opacity=0);
position:absolute;
top:5px;
width:1px;
z-index: -1;
}
</style>
<script type= "text/javascript ">
function MultiSelector( list_target, max ){
// Where to write the list
this.list_target = list_target;
// How many elements?
this.count = 0;
// How many elements?
this.id = 0;
// Is there a maximum?
if( max ){
this.max = max;
} else {
this.max = -1;
};
/**
* Add a new file input element
*/
this.addElement = function( element ){
// Make sure it 's a file input element
if( element.tagName == 'INPUT ' && element.type == 'file ' ){
// Element name -- what number am I?
element.name = 'file_ ' + this.id++;
// Add reference to this object
element.multi_selector = this;
// What to do when a file is selected
element.onchange = function(){
// New file input
var new_element = document.createElement( 'input ' );
new_element.type = 'file ';
new_element.size = 1;
new_element.className = "addfile ";
// Add new element
this.parentNode.insertBefore( new_element, this );
// Apply 'update ' to element
this.multi_selector.addElement( new_element );
// Update list
this.multi_selector.addListRow( this );
// Hide this: we can 't use display:none because Safari doesn 't like it
this.style.position = 'absolute ';
this.style.left = '-1000px ';
};
// If we 've reached maximum number, disable input element
if( this.max != -1 && this.count > = this.max ){
element.disabled = true;
};
// File element counter
this.count++;
// Most recent element
this.current_element = element;
} else {
// This can only be applied to file input elements!
alert( 'Error: not a file input element ' );
};
};
/**
* Add a new row to the list of files
*/
this.addListRow = function( element ){
// Row div
var new_row = document.createElement( 'div ' );
// Delete button
var new_row_button = document.createElement( 'input ' );
new_row_button.type = 'button ';
new_row_button.value = 'Delete ';
// References
new_row.element = element;
// Delete function
new_row_button.onclick= function(){
// Remove element from form
this.parentNode.element.parentNode.removeChild( this.parentNode.element );
// Remove this row from the list
this.parentNode.parentNode.removeChild( this.parentNode );
// Decrement counter
this.parentNode.element.multi_selector.count--;
// Re-enable input element (if it 's disabled)