JavaScript实现的文本框placeholder提示文字功能示例
筱葭 人气:0本文实例讲述了JavaScript实现的文本框placeholder提示文字功能。分享给大家供大家参考,具体如下:
<!doctype html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>www.qb5200.com JS文本框placeholder提示</title> </head> <body> <input id="input" type="text" value="请输入关键词"> </body> <script> window.onload = function() { var defaultValue = "请输入关键词"; var input = document.getElementById("input"); input.style.color = "grey"; input.onfocus = function() { if (this.value == defaultValue) { input.value=""; setCursorPosition(this, 0); } }; input.onblur = function() { if (this.value == "") { this.value = defaultValue; } }; input.onkeypress = function(e) { e = e || window.event; var key = e.charCode || e.keyCode || e.which; if (this.value == defaultValue) { this.value = ""; this.style.color = "black"; } if (this.value.length == 1 && key == 8) { this.value = defaultValue; this.style.color = "grey"; setCursorPosition(this, 0); } }; }; function setCursorPosition(elem, index) { if (elem.setSelectionRange) { elem.focus(); elem.setSelectionRange(index, index); } else if (elem.createTextRange) { var range = elem.createTextRange(); range.collapse(true); range.moveEnd('character', index); range.moveStart('character', index); range.select(); } } </script> </html>
感兴趣的朋友可以使用在线HTML/CSS/JavaScript代码运行工具:http://tools.softyun.net/code/HtmlJsRun测试一下运行效果。
希望本文所述对大家JavaScript程序设计有所帮助。
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