Regular Expression Tester

Written in JS, from regular-expressions.info

by Preston Badeer

HTML

<form id="demoMatch" name="demoMatch" method="post" action="javascript:void(0)">
    <p>Regexp:
        <input type="text" name="regex" value="\bt[a-z]+\b" size="50" />
    </p>
    <p>Subject string:
        <input type="text" name="subject" value="This is a test of the JavaScript RegExp object" size="50" />
    </p>
    <p>
        <input type="submit" value="Test Match" onclick="demoMatchClick()" />
        <input type="submit" value="Show Match" onclick="demoShowMatchClick()" />
    </p>
    <P>Replacement text:
        <input type="text" name="replacement" value="replaced" size="50" />
    </P>
    <p>Result:
        <input type="text" name="result" value="click the button to see the result" size="50" />
    </p>
    <p>
        <input type="submit" value="Replace" onclick="demoReplaceClick()"/>
    </p>
</form>

JavaScript

function demoMatchClick() {
    var re = new RegExp(document.demoMatch.regex.value);
    if (document.demoMatch.subject.value.match(re)) {
        alert("Successful match");
    } else {
        alert("No match");
    }
}

function demoShowMatchClick() {
    var re = new RegExp(document.demoMatch.regex.value);
    var m = re.exec(document.demoMatch.subject.value);
    if (m == null) {
        alert("No match");
    } else {
        var s = "Match at position " + m.index + ":\n";
        for (i = 0; i < m.length; i++) {
            s = s + m[i] + "\n";
        }
        alert(s);
    }
}

function demoReplaceClick() {
    var re = new RegExp(document.demoMatch.regex.value, "g");
    document.demoMatch.result.value = document.demoMatch.subject.value.replace(re,
    document.demoMatch.replacement.value);
}