title: Uglify - javascript error coming using the uglified clubbed file
body: <p>I am using grunt to club various javascript files and minify them all. e.g</p>
  
  <pre><code>module.exports = function (grunt) {
      grunt.initConfig({
          uglify: {
              build: {
                  src: ['js/jquery-1.7.min.js','js/common.js','js/drop_down.js', 'js/main_jquery.js', 'js/tooltip.js', 'js/html5shiv.js','js/MathJax/MathJax.js','js/angular-1.2.15.min.js','js/ui-bootstrap-tpls-0.9.0.js'],
                  dest: 'js/output.min.js'
              }
          }
      });
      grunt.loadNpmTasks('grunt-contrib-uglify');
      grunt.registerTask('default', ['uglify']);
  </code></pre>
  
  <p>On using <code>output.js</code> in place of src files, I am getting surprising javascript errors.</p>
  
  <p>e.g.This error results from the $injector being unable to resolve a required dependency. To fix this, make sure the dependency is defined and spelled correctly.</p>
  
  <p>I am curious to know how does <code>uglify</code> deal with variables with same name in two files. What could all be the reason for javascript errors?</p>