Listing A
var regex="";
var teststr="";

function validate_one()
{
       regex=/^\d{5} \d{6}$/;
       teststr=document.re1.areacode.value + " " + document.re1.phoneno.value;

       if (regex.test(teststr))
       {
              alert("Valid phone number");
       }
       else
       {
              alert("Not a valid phone number");
       }
}

function validate_two()
{
       document.re2.longtext.value=document.re2.longtext.value.replace(/2002/g,"2003");
}

function validate_three()
{
       regex=/^\d\d\d\d\d$/;
       teststr=document.re3.fivedigits.value;

       if (regex.test(teststr))
       {
              alert("Five Digits");
       }
       else
       {
              alert("Not Five Digits");
       }
}

function validate_four()
{
       regex=/^\d{1,3}$/;
       teststr=document.re4.one2threedigits.value;

       if (regex.test(teststr))
       {
              alert("Between one and three digits");
       }
       else
       {
              alert("Not between one and three digits");
       }
}

function validate_five()
{
       regex=/^[a,b,c,x,y,z]{3}\d{3}$/;
       teststr=document.re5.complexpattern.value;

       if (regex.test(teststr))
       {
              alert("Matches");
       }
       else
       {
              alert("Does not Match");
       }
}

function testRE()
{
       var myregex=new RegExp("test");

       myregex.compile(document.re6.myregex.value);
       teststr=document.re6.mysample.value;

       if (myregex.test(teststr))
       {
              alert("Matches");
       }
       else
       {
              alert("Does not Match");
       }
}

function testRE1()
{
       var myregex=new RegExp("test");
       var replaceWith=document.re6.replacewith.value;
       var argstring="";

       // check for arguments
       if (document.re6.global.checked)
       {
              argstring = argstring + "g";
       }
       if (document.re6.caseinsensitive.checked)
       {
              argstring = argstring + "i";
       }

       // if we have arguments
       if (argstring.length>0)
       {
              myregex.compile(document.re6.myregex1.value,argstring);
       }
       else
       {
              myregex.compile(document.re6.myregex1.value);
       }

       teststr=document.re6.mysample1.value;

       document.re6.mysample1.value=teststr.replace(myregex,replaceWith);
}