Using WITH(...) in JavaScript

Thursday, November 10, 2005 11:04:00 PM

Some days ago I had a look in some Visual Basic source code and found the WITH statement there. I was thinking about how I can use this in JavaScript code. Below you will find a very simple script that allows you to use the With method (that will reduce your source code size of JavaScript files):

<html><body>

<style>
.myclassname {font-family:arial;}
</style>

<div id="test">My dummy text.</div>

<script type="text/javascript">

function With(o, p) {
  for(var prop in p) {
    o[prop] = p[prop];
  }
}

var ele = document.getElementById("test");

With(ele.style, {
  color:"red",
  fontSize:"12px",
  backgroundColor:"yellow"
});

With(ele, {
  className:"myclassname"
});

</script>

</body></html>

2 Comments

  • Ron Buckton said

    javascript already supports with(o) {...}

    with in js temporarily changes the global object to the specified object passed as a param to the with statement.

    Only predefined properties and expandos can be set in this way. If the object does not define the expando it will not create one:

    with(el.style)
    {
    color = &quot;black&quot;;
    }

  • Michael Schwarz said

    You are talking about the &quot;with&quot; statement of JavaScript, yes, there you can only set properties that are predefined. The new &quot;With&quot; function will set any property you specify, that is the difference.

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