ie7-compatibility.js

 $(document).ready(function () {
    var iec = new IECompatibility();
    alert('IsIE: ' + iec.IsIE + '\nVersion: ' + iec.Version + '\nCompatability On: ' + iec.IsOn);
  });

  function IECompatibility() {
    var agentStr = navigator.userAgent;
    this.IsIE = false;
    this.IsOn = undefined;  //defined only if IE
    this.Version = undefined;

    if (agentStr.indexOf("MSIE 7.0") > -1) {
      this.IsIE = true;
      this.IsOn = true;
      if (agentStr.indexOf("Trident/6.0") > -1) {
        this.Version = 'IE10';
      } else if (agentStr.indexOf("Trident/5.0") > -1) {
        this.Version = 'IE9';
      } else if (agentStr.indexOf("Trident/4.0") > -1) {
        this.Version = 'IE8';
      } else {
        this.IsOn = false; // compatability mimics 7, thus not on
        this.Version = 'IE7';
      }
    } //IE 7
  }