JS代码实用代码实例（输入框监听，点击显示点击其他地方消失,文件本地预览上传)

// QQ表情插件
(function($){  
    $.fn.qqFace = function(options){
        var defaults = {
            id : ‘facebox‘,
            path : ‘face/‘,
            assign : ‘content‘,
            tip : ‘em_‘
        };
        var option = $.extend(defaults, options);
        var assign = $(‘#‘+option.assign);
        var id = option.id;
        var path = option.path;
        var tip = option.tip;
        
        if(assign.length<=0){
            alert(‘缺少表情赋值对象。‘);
            return false;
        }
        
        $(this).click(function(e){
            var strFace, labFace;
            if($(‘#‘+id).length<=0){
                strFace = ‘<div id="‘+id+‘" style="position:absolute;display:none;z-index:1000;" class="qqFace">‘ +
                              ‘<table border="0" cellspacing="0" cellpadding="0"><tr>‘;
                for(var i=1; i<=75; i++){
                    labFace = ‘[‘+tip+i+‘]‘;
                    strFace += ‘<td><img src="‘+path+i+‘.gif" onclick="$(\‘#‘+option.assign+‘\‘).setCaret();$(\‘#‘+option.assign+‘\‘).insertAtCaret(\‘‘ + labFace + ‘\‘);" /></td>‘;
                    if( i % 15 == 0 ) strFace += ‘</tr><tr>‘;
                }
                strFace += ‘</tr></table></div>‘;
            }
            $(this).parent().append(strFace);
            var offset = $(this).position();
            var top = offset.top + $(this).outerHeight();
            $(‘#‘+id).css(‘top‘,top);
            $(‘#‘+id).css(‘left‘,offset.left);
            $(‘#‘+id).show();
            e.stopPropagation();
        });

        $(document).click(function(){
            $(‘#‘+id).hide();
            $(‘#‘+id).remove();
        });
    };

})(jQuery);

jQuery.extend({ 
unselectContents: function(){ 
    if(window.getSelection) 
        window.getSelection().removeAllRanges(); 
    else if(document.selection) 
        document.selection.empty(); 
    } 
}); 
jQuery.fn.extend({ 
    selectContents: function(){ 
        $(this).each(function(i){ 
            var node = this; 
            var selection, range, doc, win; 
            if ((doc = node.ownerDocument) && (win = doc.defaultView) && typeof win.getSelection != ‘undefined‘ && typeof doc.createRange != ‘undefined‘ && (selection = window.getSelection()) && typeof selection.removeAllRanges != ‘undefined‘){ 
                range = doc.createRange(); 
                range.selectNode(node); 
                if(i == 0){ 
                    selection.removeAllRanges(); 
                } 
                selection.addRange(range); 
            } else if (document.body && typeof document.body.createTextRange != ‘undefined‘ && (range = document.body.createTextRange())){ 
                range.moveToElementText(node); 
                range.select(); 
            } 
        }); 
    }, 

    setCaret: function(){ 
        //if(!$.browser.msie) return;
        var initSetCaret = function(){
            var textObj = $(this).get(0);
            //textObj.caretPos = document.selection.createRange().duplicate();
        };
        $(this).click(initSetCaret).select(initSetCaret).keyup(initSetCaret); 
    }, 

    insertAtCaret: function(textFeildValue){ 
        var textObj = $(this).get(0); 
        if(document.all && textObj.createTextRange && textObj.caretPos){ 
            var caretPos=textObj.caretPos; 
            caretPos.text = caretPos.text.charAt(caretPos.text.length-1) == ‘‘ ? 
            textFeildValue+‘‘ : textFeildValue; 
        } else if(textObj.setSelectionRange){ 
            var rangeStart=textObj.selectionStart; 
            var rangeEnd=textObj.selectionEnd; 
            var tempStr1=textObj.value.substring(0,rangeStart); 
            var tempStr2=textObj.value.substring(rangeEnd); 
            textObj.value=tempStr1+textFeildValue+tempStr2; 
            textObj.focus(); 
            var len=textFeildValue.length; 
            textObj.setSelectionRange(rangeStart+len,rangeStart+len); 
            textObj.blur(); 
        }else{ 
            textObj.value+=textFeildValue; 
        } 
    } 
});

function handleFileSelect(evt) {
    var files = evt.target.files;

    // Loop through the FileList and render image files as thumbnails.
    for (var i = 0, f; f = files[i]; i++) {

      // Only process image files.
      if (!f.type.match(‘image.*‘)) {
        continue;
      }

      var reader = new FileReader();

      // Closure to capture the file information.
      reader.onload = (function(theFile) {
        return function(e) {
          // Render thumbnail.
          var span = document.createElement(‘span‘);
          span.innerHTML = 
          [
            ‘<img style="height: 75px; border: 1px solid #000; margin: 5px" src="‘, 
            e.target.result,
            ‘" title="‘, escape(theFile.name), 
            ‘"/>‘
          ].join(‘‘);
          
          document.getElementById(‘list‘).insertBefore(span, null);
        };
      })(f);

      // Read in the image file as a data URL.
      reader.readAsDataURL(f);
    }
  }

  document.getElementById(‘files‘).addEventListener(‘change‘, handleFileSelect, false);