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Js原生 双向数据绑定

2016-07-21 20:50 543 查看
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Demo</title>
<script>
function DataBinder( object_id ) {
// Create a simple PubSub object
var pubSub = {
callbacks: {},

on: function( msg, callback ) {
this.callbacks[ msg ] = this.callbacks[ msg ] || [];
this.callbacks[ msg ].push( callback );
},

publish: function( msg ) {
this.callbacks[ msg ] = this.callbacks[ msg ] || [];
for ( var i = 0, len = this.callbacks[ msg ].length; i < len; i++ ) {
this.callbacks[ msg ][ i ].apply( this, arguments );
}
}
},

data_attr = "data-bind-" + object_id,
message = object_id + ":input",
timeIn;

changeHandler = function( evt ) {
var target = evt.target || evt.srcElement, // IE8 compatibility
prop_name = target.getAttribute( data_attr );

if ( prop_name && prop_name !== "" ) {
clearTimeout(timeIn);
timeIn = setTimeout(function(){
pubSub.publish( message, prop_name, target.value );
},50);

}
};

// Listen to change events and proxy to PubSub
if ( document.addEventListener ) {
document.addEventListener( "input", changeHandler, false );
} else {
// IE8 uses attachEvent instead of addEventListener
document.attachEvent( "oninput", changeHandler );
}

// PubSub propagates changes to all bound elements
pubSub.on( message, function( evt, prop_name, new_val ) {
var elements = document.querySelectorAll("[" + data_attr + "=" + prop_name + "]"),
tag_name;

for ( var i = 0, len = elements.length; i < len; i++ ) {
tag_name = elements[ i ].tagName.toLowerCase();

if ( tag_name === "input" || tag_name === "textarea" || tag_name === "select" ) {
elements[ i ].value = new_val;
} else {
elements[ i ].innerHTML = new_val;
}
}
});

return pubSub;
}
function DBind( uid ) {
var binder = new DataBinder( uid ),

user = {
// ...
attributes: {},
set: function( attr_name, val ) {
this.attributes[ attr_name ] = val;
// Use the `publish` method
binder.publish( uid + ":input", attr_name, val, this );
},
get: function( attr_name ) {
return this.attributes[ attr_name ];
},

_binder: binder
};

// Subscribe to the PubSub
binder.on( uid + ":input", function( evt, attr_name, new_val, initiator ) {
if ( initiator !== user ) {
user.set( attr_name, new_val );
}
});

return user;
}

</script>
</head>
<body>
<input type="text" data-bind-1="name" />
<span data-bind-1="name"></span>
<script>
var DBind = new DBind( 1 );
DBind.set( "name", "黄奇" );
</script>
</body>
</html>
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