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Example 7.11:
Built-in Functions--eval
This page uses a built-in function, eval(form.txtCalc.value), to return the value of a calculation made using a string returned from a form.
These are the scripts we used. First, in the HEAD:
<![CDATA[
<SCRIPT LANGUAGE="JavaScript">
<!--
function GetNumbers(form) {
form.txtResult.value= eval(form.txtCalc.value)
}
//-->
</SCRIPT>
]]>
Later in the Web page the function is called from this form:
<![CDATA[
<FORM>
Enter a calculation (for example, (3*7)/11 ): <INPUT TYPE="text" NAME="txtCalc" SIZE=12><P>
<INPUT TYPE="button" VALUE="Result" onclick="GetNumbers(this.form)"> <INPUT TYPE="text" NAME="txtResult" SIZE=20>
</FORM>
]]>
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