js下載

下載用ajax很差使,得用表單提交的方式

download:function(url,paramObj){
			var doc = document;
			//使用一個隱藏的form表單執行提交，沒有則建立
			var downloadForm = doc.getElementById('_downloadForm');
			if(!downloadForm){
				
				downloadForm = doc.createElement('form');
				downloadForm.id = '_downloadForm';
				
				doc.body.appendChild(downloadForm);//必須加入body中，不然可能不下載
			}
			
			downloadForm.method = 'post';
			downloadForm.action = url;
			downloadForm.style.display='none';//隱藏
			downloadForm.target='_blank';
			
			//移除以前表單內的全部域
			while(downloadForm.hasChildNodes()){
				downloadForm.removeChild(downloadForm.firstChild);
		    }
			
			//根據傳入的參數，建立表單隱藏域
			if(paramObj != null){
				var hidden;
				for(var key in paramObj){ 
			        if(paramObj[key]==null || paramObj[key] == undefined){
			        	continue;
			        }
					
					hidden = doc.createElement('input');
					hidden.type='hidden';
					hidden.name = key;
					hidden.value = paramObj[key];
					
					downloadForm.appendChild(hidden);
					
			     } 
			}
			downloadForm.submit();//提交，執行下載
		}