getExpression Method
Retrieves the expression for the given property.
Syntax
vExpression = object.getExpression(sPropertyName)
Parameters
sPropertyName Required. String that specifies the name of the property from which to retrieve the expression.
Return Value
Variant. Returns a variant value representing the expression of the property.
Remarks
The following syntax sections show how to retrieve an expression from supported Cascading Style Sheets (CSS) and DHTML Properties.
Use this syntax to retrieve an expression from a read/write property or from an expando property.
var sExpression = object.getExpression(sPropertyName)
Use this syntax to retrieve an expression from a CSS attribute.
var sExpression = object.style.getExpression(sPropertyName)
Examples
The following examples demonstrate how to use the getExpression method to retrieve CSS properties.
This example uses the getExpression method to retrieve the width property of a span object.
<body>
<span id="trueBlueSpan"
style="background-color:lightblue; width:100px">
The width of this blue span is set inline at 100 pixels.
</span>
<span id="oldYellowSpan" style="background-color:lightyellow;
width:200px">
The width of this yelllow span is set inline at 200 pixels.
</span>
<br>
<span id="AlGreenSpan" style="background-color:lightgreen;
width:expression(trueBlueSpan.style.pixelWidth +
oldYellowSpan.style.pixelWidth)">
Click the button below to see the expression used to set
the width of this span.
</span>
<br>
<button onclick=alert(AlGreenSpan.style.getExpression("width"));>
See Expression</button>
</body>
In the following example, the setExpression method is used to set the width property of a blue input type=text object equal to the sum of the values in two other input type=text objects. When the user clicks the input type=button element, the getExpression method is used to display the expression.
<html>
<head>
<script language="JScript">
var s;
function fnInit() {
Box3.style.setExpression("width","eval(Box1.value) + eval(Box2.value)",
"jscript");
}
function getexp() {
s=Box3.style.getExpression("width");
alert("Expression for the width of the blue box is \n\n" + s +
"\n\nThe width property has a value of " + Box3.style.width);
}
</script>
</head>
<body onload=fnInit();>
<input type=text id="Box1" value=40>
<br><input type=text id="Box2" value=40>
<br><input type=text id="Box3" style="background-color:blue">
<br><input type=button id="Button2" value="Get expression" onclick="getexp()">
</body>
</html>
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