显示输入提示，获取焦点提示取消

JS

window.onload = function(){
	var setCss = function(_this, cssOption){//设置样式
			if ( !_this || _this.nodeType === 3 || _this.nodeType === 8 || !_this.style ) {
				return;
			}
			for(var cs in cssOption){
				_this.style[cs] = cssOption[cs];
			}
			return _this;
		},
			hintInput = document.getElementById("hintInput"),
			_span = document.createElement("span"),
			dataHint = hintInput.getAttribute("data-hint");
	_span.innerText = dataHint;
	setCss(_span, {
		"position":"absolute",
		"left":hintInput.offsetLeft+2,
		"top":hintInput.offsetTop,
		"zIndex":2
	});
	_span.className = "hintInput";
	hintInput.value = "";
	_span.setAttribute("id" ,"hint0");
	hintInput.parentNode.insertBefore(_span,hintInput);

	var onhint = function(e){//隐藏元素
		setCss(_span, {
			"display":"none"
		})
		hintInput.focus();


	}
	hintInput.onblur = function(e){//失去焦点显示元素
		if(!hintInput.value.replace( /^(\s|\u00A0)+|(\s|\u00A0)+$/g, "" )){
			setCss(_span, {
				"display":"block"
			})
		}

	}
	_span.onclick = hintInput.onfocus = onhint;//单击事件与获取焦点事件使用同一个函数处理
};